Spike's Tactical Complete Upper Receiver, 223 Rem/556NATO, 16" Chrome Lined Barrel, 1:7 Twist, Fits AR Rifles, Flat Top Receiver, A2 Front Sights, Black Finish STU5025-M4S
Specifications:

Type	Complete Gas Impingement
Caliber	223 Remington/5.56 NATO
Sights	A2 Front
Barrel Length	16"
Barrel Material
Twist	1:7"
Barrel Description	M4 Profile
Barrel Finish	Black
Receiver Description
Receiver Finish	Black
Handguards	Carbine Length
Handguard Finish	Black
Barrel Length Range	16.00" to 17.99"