diff --git a/lib/protocol/http/headers.rb b/lib/protocol/http/headers.rb
index 69e386b..0080458 100644
--- a/lib/protocol/http/headers.rb
+++ b/lib/protocol/http/headers.rb
@@ -64,13 +64,15 @@ def self.[] headers
 			# Initialize the headers with the specified fields.
 			#
 			# @parameter fields [Array] An array of `[key, value]` pairs.
-			# @parameter indexed [Hash] A hash table of normalized headers, if available.
-			def initialize(fields = [], indexed = nil)
+			# @parameter tail [Integer | Nil] The index of the trailer start in the @fields array.
+			def initialize(fields = [], tail = nil, indexed: nil)
 				@fields = fields
-				@indexed = indexed
 				
-				# Marks where trailer start in the @fields array.
-				@tail = nil
+				# Marks where trailer start in the @fields array:
+				@tail = tail
+				
+				# The cached index of headers:
+				@indexed = nil
 			end
 			
 			# Initialize a copy of the headers.
@@ -86,8 +88,8 @@ def initialize_dup(other)
 			# Clear all headers.
 			def clear
 				@fields.clear
-				@indexed = nil
 				@tail = nil
+				@indexed = nil
 			end
 			
 			# Flatten trailer into the headers, in-place.
@@ -108,6 +110,9 @@ def flatten
 			# @attribute [Array] An array of `[key, value]` pairs.
 			attr :fields
 			
+			# @attribute [Integer | Nil] The index where trailers begin.
+			attr :tail
+			
 			# @returns [Array] The fields of the headers.
 			def to_a
 				@fields
diff --git a/releases.md b/releases.md
index 20ddb4f..31d0c19 100644
--- a/releases.md
+++ b/releases.md
@@ -3,6 +3,7 @@
 ## Unreleased
 
   - Add `Protocol::HTTP::Headers#to_a` method that returns the fields array, providing compatibility with standard Ruby array conversion pattern.
+  - Expose `tail` in `Headers.new` so that trailers can be accurately reproduced.
 
 ## v0.51.0
 
diff --git a/test/protocol/http/headers.rb b/test/protocol/http/headers.rb
index 3bb150f..9db3fd7 100644
--- a/test/protocol/http/headers.rb
+++ b/test/protocol/http/headers.rb
@@ -10,15 +10,25 @@
 	let(:fields) do
 		[
 			["Content-Type", "text/html"],
+			["connection", "Keep-Alive"],
 			["Set-Cookie", "hello=world"],
 			["Accept", "*/*"],
 			["set-cookie", "foo=bar"],
-			["connection", "Keep-Alive"]
 		]
 	end
 	
 	let(:headers) {subject[fields]}
 	
+	with ".new" do
+		it "can construct headers with trailers" do
+			headers = subject.new(fields, 4)
+			expect(headers).to be(:trailer?)
+			expect(headers.trailer.to_a).to be == [
+				["set-cookie", "foo=bar"],
+			]
+		end
+	end
+	
 	with ".[]" do
 		it "can be constructed from frozen array" do
 			self.fields.freeze
@@ -29,13 +39,14 @@
 	
 	with "#keys" do
 		it "should return keys" do
-			expect(headers.keys).to be == ["content-type", "set-cookie", "accept", "connection"]
+			expect(headers.keys).to be == ["content-type", "connection", "set-cookie", "accept"]
 		end
 	end
 	
 	with "#trailer?" do
 		it "should not be a trailer" do
 			expect(headers).not.to be(:trailer?)
+			expect(headers.tail).to be_nil
 		end
 	end
 	
@@ -269,8 +280,10 @@
 	with "#trailer!" do
 		it "can add trailer" do
 			headers.add("trailer", "etag")
+			count = headers.fields.size
 			
 			trailer = headers.trailer!
+			expect(headers.tail).to be == count
 			
 			headers.add("etag", "abcd")
 			
@@ -345,8 +358,8 @@
 describe Protocol::HTTP::Headers::Merged do
 	let(:merged) do
 		Protocol::HTTP::Headers::Merged.new(
-			Protocol::HTTP::Headers.new("content-type" => "text/html"),
-			Protocol::HTTP::Headers.new("content-encoding" => "gzip")
+			Protocol::HTTP::Headers["content-type" => "text/html"],
+			Protocol::HTTP::Headers["content-encoding" => "gzip"]
 		)
 	end
 	
@@ -382,8 +395,8 @@
 	with "non-normalized case" do
 		let(:merged) do
 			Protocol::HTTP::Headers::Merged.new(
-				Protocol::HTTP::Headers.new("Content-Type" => "text/html"),
-				Protocol::HTTP::Headers.new("Content-Encoding" => "gzip")
+				Protocol::HTTP::Headers["Content-Type" => "text/html"],
+				Protocol::HTTP::Headers["Content-Encoding" => "gzip"]
 			)
 		end