Surefire SFM-556-1/2 -28

Surefire muzzle flash suppressor, this works a a muzzle flash suppressor and also will serve as a collar for a Surefire suppressor, it has been used slightly and is in excellent condition and retails for $149.00, it is threaded 1/2 X 28 which is the standard thread pitch for M-16 and Ar-15 rifles, it must be used with crush washers in order to position it properly