This is a Palmetto State Armory 10.5" Phosphate A2 1:7 Twist Carbine Upper Assembly. Built by PSA and made in the USA!!Barrel Length 10.5" 5.56 Nato Chamber1 in 7" twist Carbine-length Gas Phosphate Finish.750" Gas Block Diameter M4 Feedramps Forged Upper **Upper may or may not have T-marksUpper Includes Black Nitride BCG w/ Std Charging Handle