This Daniel Defense M4A1 FSP AR15 style Upper Receiver Group was built for customers wanting a firearm inspired by USSOCOM SOPMOD Block II. This upper features the M4A1 FSP RIS II picatinny quad rail in Flat Dark Earth, a 14.5″ M4 profile barrel, Mil-Spec F-Marked front sight base, Surefire SF3P flash hider / suppressor adapter, A1.5 Fixed Rear Sight, M16 profile full auto bolt carrier group, and Rail Mounted QD Swivel Attachment Point with QD swivel.