diff --git a/BleKeyboard.cpp b/BleKeyboard.cpp
index 48a8930..2b2c495 100644
--- a/BleKeyboard.cpp
+++ b/BleKeyboard.cpp
@@ -1,3 +1,6 @@
+// uncomment the following line to use NimBLE library
+//#define USE_NIMBLE
+
 #include "BleKeyboard.h"
 
 #if defined(USE_NIMBLE)
@@ -95,40 +98,37 @@ static const uint8_t _hidReportDescriptor[] = {
   END_COLLECTION(0)                  // END_COLLECTION
 };
 
-BleKeyboard::BleKeyboard(std::string deviceName, std::string deviceManufacturer, uint8_t batteryLevel) 
+BleKeyboard::BleKeyboard(String deviceName, String deviceManufacturer, uint8_t batteryLevel) 
     : hid(0)
-    , deviceName(std::string(deviceName).substr(0, 15))
-    , deviceManufacturer(std::string(deviceManufacturer).substr(0,15))
+    , deviceName(deviceName.substring(0, 15))
+    , deviceManufacturer(deviceManufacturer.substring(0, 15))
     , batteryLevel(batteryLevel) {}
 
 void BleKeyboard::begin(void)
 {
+  // FIX 1: pass String directly — no redundant c_str() round-trip
   BLEDevice::init(deviceName);
   BLEServer* pServer = BLEDevice::createServer();
   pServer->setCallbacks(this);
 
   hid = new BLEHIDDevice(pServer);
-  inputKeyboard = hid->inputReport(KEYBOARD_ID);  // <-- input REPORTID from report map
+  inputKeyboard = hid->inputReport(KEYBOARD_ID);
   outputKeyboard = hid->outputReport(KEYBOARD_ID);
   inputMediaKeys = hid->inputReport(MEDIA_KEYS_ID);
 
   outputKeyboard->setCallbacks(this);
 
+  // FIX 2: pass String directly
   hid->manufacturer()->setValue(deviceManufacturer);
 
   hid->pnp(0x02, vid, pid, version);
   hid->hidInfo(0x00, 0x01);
 
-
 #if defined(USE_NIMBLE)
-
   BLEDevice::setSecurityAuth(true, true, true);
-
 #else
-
   BLESecurity* pSecurity = new BLESecurity();
   pSecurity->setAuthenticationMode(ESP_LE_AUTH_REQ_SC_MITM_BOND);
-
 #endif // USE_NIMBLE
 
   hid->reportMap((uint8_t*)_hidReportDescriptor, sizeof(_hidReportDescriptor));
@@ -160,30 +160,24 @@ void BleKeyboard::setBatteryLevel(uint8_t level) {
     this->hid->setBatteryLevel(this->batteryLevel);
 }
 
-//must be called before begin in order to set the name
-void BleKeyboard::setName(std::string deviceName) {
+void BleKeyboard::setName(String deviceName) {
   this->deviceName = deviceName;
 }
 
-/**
- * @brief Sets the waiting time (in milliseconds) between multiple keystrokes in NimBLE mode.
- * 
- * @param ms Time in milliseconds
- */
 void BleKeyboard::setDelay(uint32_t ms) {
   this->_delay_ms = ms;
 }
 
 void BleKeyboard::set_vendor_id(uint16_t vid) { 
-	this->vid = vid; 
+  this->vid = vid; 
 }
 
 void BleKeyboard::set_product_id(uint16_t pid) { 
-	this->pid = pid; 
+  this->pid = pid; 
 }
 
 void BleKeyboard::set_version(uint16_t version) { 
-	this->version = version; 
+  this->version = version; 
 }
 
 void BleKeyboard::sendReport(KeyReport* keys)
@@ -193,7 +187,6 @@ void BleKeyboard::sendReport(KeyReport* keys)
     this->inputKeyboard->setValue((uint8_t*)keys, sizeof(KeyReport));
     this->inputKeyboard->notify();
 #if defined(USE_NIMBLE)        
-    // vTaskDelay(delayTicks);
     this->delay_ms(_delay_ms);
 #endif // USE_NIMBLE
   }	
@@ -206,7 +199,6 @@ void BleKeyboard::sendReport(MediaKeyReport* keys)
     this->inputMediaKeys->setValue((uint8_t*)keys, sizeof(MediaKeyReport));
     this->inputMediaKeys->notify();
 #if defined(USE_NIMBLE)        
-    //vTaskDelay(delayTicks);
     this->delay_ms(_delay_ms);
 #endif // USE_NIMBLE
   }	
@@ -218,319 +210,306 @@ const uint8_t _asciimap[128] PROGMEM;
 #define SHIFT 0x80
 const uint8_t _asciimap[128] =
 {
-	0x00,             // NUL
-	0x00,             // SOH
-	0x00,             // STX
-	0x00,             // ETX
-	0x00,             // EOT
-	0x00,             // ENQ
-	0x00,             // ACK
-	0x00,             // BEL
-	0x2a,			// BS	Backspace
-	0x2b,			// TAB	Tab
-	0x28,			// LF	Enter
-	0x00,             // VT
-	0x00,             // FF
-	0x00,             // CR
-	0x00,             // SO
-	0x00,             // SI
-	0x00,             // DEL
-	0x00,             // DC1
-	0x00,             // DC2
-	0x00,             // DC3
-	0x00,             // DC4
-	0x00,             // NAK
-	0x00,             // SYN
-	0x00,             // ETB
-	0x00,             // CAN
-	0x00,             // EM
-	0x00,             // SUB
-	0x00,             // ESC
-	0x00,             // FS
-	0x00,             // GS
-	0x00,             // RS
-	0x00,             // US
-
-	0x2c,		   //  ' '
-	0x1e|SHIFT,	   // !
-	0x34|SHIFT,	   // "
-	0x20|SHIFT,    // #
-	0x21|SHIFT,    // $
-	0x22|SHIFT,    // %
-	0x24|SHIFT,    // &
-	0x34,          // '
-	0x26|SHIFT,    // (
-	0x27|SHIFT,    // )
-	0x25|SHIFT,    // *
-	0x2e|SHIFT,    // +
-	0x36,          // ,
-	0x2d,          // -
-	0x37,          // .
-	0x38,          // /
-	0x27,          // 0
-	0x1e,          // 1
-	0x1f,          // 2
-	0x20,          // 3
-	0x21,          // 4
-	0x22,          // 5
-	0x23,          // 6
-	0x24,          // 7
-	0x25,          // 8
-	0x26,          // 9
-	0x33|SHIFT,      // :
-	0x33,          // ;
-	0x36|SHIFT,      // <
-	0x2e,          // =
-	0x37|SHIFT,      // >
-	0x38|SHIFT,      // ?
-	0x1f|SHIFT,      // @
-	0x04|SHIFT,      // A
-	0x05|SHIFT,      // B
-	0x06|SHIFT,      // C
-	0x07|SHIFT,      // D
-	0x08|SHIFT,      // E
-	0x09|SHIFT,      // F
-	0x0a|SHIFT,      // G
-	0x0b|SHIFT,      // H
-	0x0c|SHIFT,      // I
-	0x0d|SHIFT,      // J
-	0x0e|SHIFT,      // K
-	0x0f|SHIFT,      // L
-	0x10|SHIFT,      // M
-	0x11|SHIFT,      // N
-	0x12|SHIFT,      // O
-	0x13|SHIFT,      // P
-	0x14|SHIFT,      // Q
-	0x15|SHIFT,      // R
-	0x16|SHIFT,      // S
-	0x17|SHIFT,      // T
-	0x18|SHIFT,      // U
-	0x19|SHIFT,      // V
-	0x1a|SHIFT,      // W
-	0x1b|SHIFT,      // X
-	0x1c|SHIFT,      // Y
-	0x1d|SHIFT,      // Z
-	0x2f,          // [
-	0x31,          // bslash
-	0x30,          // ]
-	0x23|SHIFT,    // ^
-	0x2d|SHIFT,    // _
-	0x35,          // `
-	0x04,          // a
-	0x05,          // b
-	0x06,          // c
-	0x07,          // d
-	0x08,          // e
-	0x09,          // f
-	0x0a,          // g
-	0x0b,          // h
-	0x0c,          // i
-	0x0d,          // j
-	0x0e,          // k
-	0x0f,          // l
-	0x10,          // m
-	0x11,          // n
-	0x12,          // o
-	0x13,          // p
-	0x14,          // q
-	0x15,          // r
-	0x16,          // s
-	0x17,          // t
-	0x18,          // u
-	0x19,          // v
-	0x1a,          // w
-	0x1b,          // x
-	0x1c,          // y
-	0x1d,          // z
-	0x2f|SHIFT,    // {
-	0x31|SHIFT,    // |
-	0x30|SHIFT,    // }
-	0x35|SHIFT,    // ~
-	0				// DEL
+  0x00,             // NUL
+  0x00,             // SOH
+  0x00,             // STX
+  0x00,             // ETX
+  0x00,             // EOT
+  0x00,             // ENQ
+  0x00,             // ACK
+  0x00,             // BEL
+  0x2a,             // BS   Backspace
+  0x2b,             // TAB  Tab
+  0x28,             // LF   Enter
+  0x00,             // VT
+  0x00,             // FF
+  0x00,             // CR
+  0x00,             // SO
+  0x00,             // SI
+  0x00,             // DEL
+  0x00,             // DC1
+  0x00,             // DC2
+  0x00,             // DC3
+  0x00,             // DC4
+  0x00,             // NAK
+  0x00,             // SYN
+  0x00,             // ETB
+  0x00,             // CAN
+  0x00,             // EM
+  0x00,             // SUB
+  0x00,             // ESC
+  0x00,             // FS
+  0x00,             // GS
+  0x00,             // RS
+  0x00,             // US
+
+  0x2c,              //  ' '
+  0x1e|SHIFT,        // !
+  0x34|SHIFT,        // "
+  0x20|SHIFT,        // #
+  0x21|SHIFT,        // $
+  0x22|SHIFT,        // %
+  0x24|SHIFT,        // &
+  0x34,              // '
+  0x26|SHIFT,        // (
+  0x27|SHIFT,        // )
+  0x25|SHIFT,        // *
+  0x2e|SHIFT,        // +
+  0x36,              // ,
+  0x2d,              // -
+  0x37,              // .
+  0x38,              // /
+  0x27,              // 0
+  0x1e,              // 1
+  0x1f,              // 2
+  0x20,              // 3
+  0x21,              // 4
+  0x22,              // 5
+  0x23,              // 6
+  0x24,              // 7
+  0x25,              // 8
+  0x26,              // 9
+  0x33|SHIFT,        // :
+  0x33,              // ;
+  0x36|SHIFT,        // <
+  0x2e,              // =
+  0x37|SHIFT,        // >
+  0x38|SHIFT,        // ?
+  0x1f|SHIFT,        // @
+  0x04|SHIFT,        // A
+  0x05|SHIFT,        // B
+  0x06|SHIFT,        // C
+  0x07|SHIFT,        // D
+  0x08|SHIFT,        // E
+  0x09|SHIFT,        // F
+  0x0a|SHIFT,        // G
+  0x0b|SHIFT,        // H
+  0x0c|SHIFT,        // I
+  0x0d|SHIFT,        // J
+  0x0e|SHIFT,        // K
+  0x0f|SHIFT,        // L
+  0x10|SHIFT,        // M
+  0x11|SHIFT,        // N
+  0x12|SHIFT,        // O
+  0x13|SHIFT,        // P
+  0x14|SHIFT,        // Q
+  0x15|SHIFT,        // R
+  0x16|SHIFT,        // S
+  0x17|SHIFT,        // T
+  0x18|SHIFT,        // U
+  0x19|SHIFT,        // V
+  0x1a|SHIFT,        // W
+  0x1b|SHIFT,        // X
+  0x1c|SHIFT,        // Y
+  0x1d|SHIFT,        // Z
+  0x2f,              // [
+  0x31,              // bslash
+  0x30,              // ]
+  0x23|SHIFT,        // ^
+  0x2d|SHIFT,        // _
+  0x35,              // `
+  0x04,              // a
+  0x05,              // b
+  0x06,              // c
+  0x07,              // d
+  0x08,              // e
+  0x09,              // f
+  0x0a,              // g
+  0x0b,              // h
+  0x0c,              // i
+  0x0d,              // j
+  0x0e,              // k
+  0x0f,              // l
+  0x10,              // m
+  0x11,              // n
+  0x12,              // o
+  0x13,              // p
+  0x14,              // q
+  0x15,              // r
+  0x16,              // s
+  0x17,              // t
+  0x18,              // u
+  0x19,              // v
+  0x1a,              // w
+  0x1b,              // x
+  0x1c,              // y
+  0x1d,              // z
+  0x2f|SHIFT,        // {
+  0x31|SHIFT,        // |
+  0x30|SHIFT,        // }
+  0x35|SHIFT,        // ~
+  0                  // DEL
 };
 
 
 uint8_t USBPutChar(uint8_t c);
 
-// press() adds the specified key (printing, non-printing, or modifier)
-// to the persistent key report and sends the report.  Because of the way
-// USB HID works, the host acts like the key remains pressed until we
-// call release(), releaseAll(), or otherwise clear the report and resend.
 size_t BleKeyboard::press(uint8_t k)
 {
-	uint8_t i;
-	if (k >= 136) {			// it's a non-printing key (not a modifier)
-		k = k - 136;
-	} else if (k >= 128) {	// it's a modifier key
-		_keyReport.modifiers |= (1<<(k-128));
-		k = 0;
-	} else {				// it's a printing key
-		k = pgm_read_byte(_asciimap + k);
-		if (!k) {
-			setWriteError();
-			return 0;
-		}
-		if (k & 0x80) {						// it's a capital letter or other character reached with shift
-			_keyReport.modifiers |= 0x02;	// the left shift modifier
-			k &= 0x7F;
-		}
-	}
-
-	// Add k to the key report only if it's not already present
-	// and if there is an empty slot.
-	if (_keyReport.keys[0] != k && _keyReport.keys[1] != k &&
-		_keyReport.keys[2] != k && _keyReport.keys[3] != k &&
-		_keyReport.keys[4] != k && _keyReport.keys[5] != k) {
-
-		for (i=0; i<6; i++) {
-			if (_keyReport.keys[i] == 0x00) {
-				_keyReport.keys[i] = k;
-				break;
-			}
-		}
-		if (i == 6) {
-			setWriteError();
-			return 0;
-		}
-	}
-	sendReport(&_keyReport);
-	return 1;
+  uint8_t i;
+  if (k >= 136) {
+    k = k - 136;
+  } else if (k >= 128) {
+    _keyReport.modifiers |= (1<<(k-128));
+    k = 0;
+  } else {
+    k = pgm_read_byte(_asciimap + k);
+    if (!k) {
+      setWriteError();
+      return 0;
+    }
+    if (k & 0x80) {
+      _keyReport.modifiers |= 0x02;
+      k &= 0x7F;
+    }
+  }
+
+  if (_keyReport.keys[0] != k && _keyReport.keys[1] != k &&
+    _keyReport.keys[2] != k && _keyReport.keys[3] != k &&
+    _keyReport.keys[4] != k && _keyReport.keys[5] != k) {
+
+    for (i=0; i<6; i++) {
+      if (_keyReport.keys[i] == 0x00) {
+        _keyReport.keys[i] = k;
+        break;
+      }
+    }
+    if (i == 6) {
+      setWriteError();
+      return 0;
+    }
+  }
+  sendReport(&_keyReport);
+  return 1;
 }
 
 size_t BleKeyboard::press(const MediaKeyReport k)
 {
-    uint16_t k_16 = k[1] | (k[0] << 8);
-    uint16_t mediaKeyReport_16 = _mediaKeyReport[1] | (_mediaKeyReport[0] << 8);
-
-    mediaKeyReport_16 |= k_16;
-    _mediaKeyReport[0] = (uint8_t)((mediaKeyReport_16 & 0xFF00) >> 8);
-    _mediaKeyReport[1] = (uint8_t)(mediaKeyReport_16 & 0x00FF);
-
-	sendReport(&_mediaKeyReport);
-	return 1;
+  uint16_t k_16 = k[1] | (k[0] << 8);
+  uint16_t mediaKeyReport_16 = _mediaKeyReport[1] | (_mediaKeyReport[0] << 8);
+  mediaKeyReport_16 |= k_16;
+  _mediaKeyReport[0] = (uint8_t)((mediaKeyReport_16 & 0xFF00) >> 8);
+  _mediaKeyReport[1] = (uint8_t)(mediaKeyReport_16 & 0x00FF);
+  sendReport(&_mediaKeyReport);
+  return 1;
 }
 
-// release() takes the specified key out of the persistent key report and
-// sends the report.  This tells the OS the key is no longer pressed and that
-// it shouldn't be repeated any more.
 size_t BleKeyboard::release(uint8_t k)
 {
-	uint8_t i;
-	if (k >= 136) {			// it's a non-printing key (not a modifier)
-		k = k - 136;
-	} else if (k >= 128) {	// it's a modifier key
-		_keyReport.modifiers &= ~(1<<(k-128));
-		k = 0;
-	} else {				// it's a printing key
-		k = pgm_read_byte(_asciimap + k);
-		if (!k) {
-			return 0;
-		}
-		if (k & 0x80) {							// it's a capital letter or other character reached with shift
-			_keyReport.modifiers &= ~(0x02);	// the left shift modifier
-			k &= 0x7F;
-		}
-	}
-
-	// Test the key report to see if k is present.  Clear it if it exists.
-	// Check all positions in case the key is present more than once (which it shouldn't be)
-	for (i=0; i<6; i++) {
-		if (0 != k && _keyReport.keys[i] == k) {
-			_keyReport.keys[i] = 0x00;
-		}
-	}
-
-	sendReport(&_keyReport);
-	return 1;
+  uint8_t i;
+  if (k >= 136) {
+    k = k - 136;
+  } else if (k >= 128) {
+    _keyReport.modifiers &= ~(1<<(k-128));
+    k = 0;
+  } else {
+    k = pgm_read_byte(_asciimap + k);
+    if (!k) {
+      return 0;
+    }
+    if (k & 0x80) {
+      _keyReport.modifiers &= ~(0x02);
+      k &= 0x7F;
+    }
+  }
+
+  for (i=0; i<6; i++) {
+    if (0 != k && _keyReport.keys[i] == k) {
+      _keyReport.keys[i] = 0x00;
+    }
+  }
+  sendReport(&_keyReport);
+  return 1;
 }
 
 size_t BleKeyboard::release(const MediaKeyReport k)
 {
-    uint16_t k_16 = k[1] | (k[0] << 8);
-    uint16_t mediaKeyReport_16 = _mediaKeyReport[1] | (_mediaKeyReport[0] << 8);
-    mediaKeyReport_16 &= ~k_16;
-    _mediaKeyReport[0] = (uint8_t)((mediaKeyReport_16 & 0xFF00) >> 8);
-    _mediaKeyReport[1] = (uint8_t)(mediaKeyReport_16 & 0x00FF);
-
-	sendReport(&_mediaKeyReport);
-	return 1;
+  uint16_t k_16 = k[1] | (k[0] << 8);
+  uint16_t mediaKeyReport_16 = _mediaKeyReport[1] | (_mediaKeyReport[0] << 8);
+  mediaKeyReport_16 &= ~k_16;
+  _mediaKeyReport[0] = (uint8_t)((mediaKeyReport_16 & 0xFF00) >> 8);
+  _mediaKeyReport[1] = (uint8_t)(mediaKeyReport_16 & 0x00FF);
+  sendReport(&_mediaKeyReport);
+  return 1;
 }
 
 void BleKeyboard::releaseAll(void)
 {
-	_keyReport.keys[0] = 0;
-	_keyReport.keys[1] = 0;
-	_keyReport.keys[2] = 0;
-	_keyReport.keys[3] = 0;
-	_keyReport.keys[4] = 0;
-	_keyReport.keys[5] = 0;
-	_keyReport.modifiers = 0;
-    _mediaKeyReport[0] = 0;
-    _mediaKeyReport[1] = 0;
-	sendReport(&_keyReport);
-	sendReport(&_mediaKeyReport);
+  _keyReport.keys[0] = 0;
+  _keyReport.keys[1] = 0;
+  _keyReport.keys[2] = 0;
+  _keyReport.keys[3] = 0;
+  _keyReport.keys[4] = 0;
+  _keyReport.keys[5] = 0;
+  _keyReport.modifiers = 0;
+  _mediaKeyReport[0] = 0;
+  _mediaKeyReport[1] = 0;
+  sendReport(&_keyReport);
+  sendReport(&_mediaKeyReport);
 }
 
 size_t BleKeyboard::write(uint8_t c)
 {
-	uint8_t p = press(c);  // Keydown
-	release(c);            // Keyup
-	return p;              // just return the result of press() since release() almost always returns 1
+  uint8_t p = press(c);
+  release(c);
+  return p;
 }
 
 size_t BleKeyboard::write(const MediaKeyReport c)
 {
-	uint16_t p = press(c);  // Keydown
-	release(c);            // Keyup
-	return p;              // just return the result of press() since release() almost always returns 1
+  uint16_t p = press(c);
+  release(c);
+  return p;
 }
 
 size_t BleKeyboard::write(const uint8_t *buffer, size_t size) {
-	size_t n = 0;
-	while (size--) {
-		if (*buffer != '\r') {
-			if (write(*buffer)) {
-			  n++;
-			} else {
-			  break;
-			}
-		}
-		buffer++;
-	}
-	return n;
+  size_t n = 0;
+  while (size--) {
+    if (*buffer != '\r') {
+      if (write(*buffer)) {
+        n++;
+      } else {
+        break;
+      }
+    }
+    buffer++;
+  }
+  return n;
 }
 
 void BleKeyboard::onConnect(BLEServer* pServer) {
   this->connected = true;
 
 #if !defined(USE_NIMBLE)
-
+  // FIX 3: null-check descriptors before use — core 3.x may return nullptr
   BLE2902* desc = (BLE2902*)this->inputKeyboard->getDescriptorByUUID(BLEUUID((uint16_t)0x2902));
-  desc->setNotifications(true);
-  desc = (BLE2902*)this->inputMediaKeys->getDescriptorByUUID(BLEUUID((uint16_t)0x2902));
-  desc->setNotifications(true);
+  if (desc != nullptr) desc->setNotifications(true);
 
+  desc = (BLE2902*)this->inputMediaKeys->getDescriptorByUUID(BLEUUID((uint16_t)0x2902));
+  if (desc != nullptr) desc->setNotifications(true);
 #endif // !USE_NIMBLE
-
 }
 
 void BleKeyboard::onDisconnect(BLEServer* pServer) {
   this->connected = false;
 
 #if !defined(USE_NIMBLE)
-
+  // FIX 3: null-check descriptors before use — core 3.x may return nullptr
   BLE2902* desc = (BLE2902*)this->inputKeyboard->getDescriptorByUUID(BLEUUID((uint16_t)0x2902));
-  desc->setNotifications(false);
+  if (desc != nullptr) desc->setNotifications(false);
+
   desc = (BLE2902*)this->inputMediaKeys->getDescriptorByUUID(BLEUUID((uint16_t)0x2902));
-  desc->setNotifications(false);
+  if (desc != nullptr) desc->setNotifications(false);
 
   advertising->start();
-
 #endif // !USE_NIMBLE
 }
 
 void BleKeyboard::onWrite(BLECharacteristic* me) {
-  uint8_t* value = (uint8_t*)(me->getValue().c_str());
+  // FIX 4: store getValue() result before taking c_str() —
+  // temporary String was destroyed immediately, leaving a dangling pointer
+  String rxValue = me->getValue();
+  uint8_t* value = (uint8_t*)rxValue.c_str();
   (void)value;
   ESP_LOGI(LOG_TAG, "special keys: %d", *value);
 }
@@ -540,7 +519,7 @@ void BleKeyboard::delay_ms(uint64_t ms) {
   if(ms){
     uint64_t e = (m + (ms * 1000));
     if(m > e){ //overflow
-        while(esp_timer_get_time() > e) { }
+      while(esp_timer_get_time() > e) { }
     }
     while(esp_timer_get_time() < e) {}
   }
diff --git a/BleKeyboard.h b/BleKeyboard.h
index 0736a02..8933c80 100644
--- a/BleKeyboard.h
+++ b/BleKeyboard.h
@@ -138,8 +138,8 @@ class BleKeyboard : public Print, public BLEServerCallbacks, public BLECharacter
   BLEAdvertising*    advertising;
   KeyReport          _keyReport;
   MediaKeyReport     _mediaKeyReport;
-  std::string        deviceName;
-  std::string        deviceManufacturer;
+  String             deviceName;
+  String             deviceManufacturer;
   uint8_t            batteryLevel;
   bool               connected = false;
   uint32_t           _delay_ms = 7;
@@ -150,7 +150,7 @@ class BleKeyboard : public Print, public BLEServerCallbacks, public BLECharacter
   uint16_t version   = 0x0210;
 
 public:
-  BleKeyboard(std::string deviceName = "ESP32 Keyboard", std::string deviceManufacturer = "Espressif", uint8_t batteryLevel = 100);
+  BleKeyboard(String deviceName = "ESP32 Keyboard", String deviceManufacturer = "Espressif", uint8_t batteryLevel = 100);
   void begin(void);
   void end(void);
   void sendReport(KeyReport* keys);
@@ -165,7 +165,7 @@ class BleKeyboard : public Print, public BLEServerCallbacks, public BLECharacter
   void releaseAll(void);
   bool isConnected(void);
   void setBatteryLevel(uint8_t level);
-  void setName(std::string deviceName);  
+  void setName(String deviceName);  
   void setDelay(uint32_t ms);
 
   void set_vendor_id(uint16_t vid);