Exclusive to Brownells, the FM Products 223 Wylde Upper Receivers! Available in both 12.5" and 16" lengths. These upper receivers are a monolithic design featuring M-LOK handguards with an all black finish. Uppers come assembled with barrel and handguard installed. Does not include bolt carrier group or charging handle. 12.5" Upper Receiver features Carbine Length Gas Tube 16" Upper Receiver features Mid-Length Gas Tube Monolithic Design Billet Machined .625 Low Profile Gas Block 1/8 Twist Lightweight Barrel Chambered in .223 Wylde A2 Muzzle Device, A 1/2-28 Threads M-LOK Handguard M4 Upper Receiver w Mfg: Foxtrot Mike Products