HK flash hider comes complete with mounting c-spring. Flash hiders thread onto your existing threads. If you have a new U.S. made barrel with no threading you will have to have your barrel threaded standard HK 15x1mm RH.
This is the correct flash hider for all HK9X 7.62 and 5.56mm weapons and clones including: HK91/G3/PTR, HK33/53/93, HK11/13/21/23, Etc. Also works great for the G36.
Conditions are surplus good.