Does your muzzle device or flash hider sit at a strange angle when installed? If your muzzle device has not method of alignment then this is what you need.

This set of shims and o-rings allow fine tuning to line up you flash hider. Works great for barrel extensions too.

Set contains:
5x 0.1mm shims
5x 0.2mm shims
1x 1mm o-ring
1x 1.5mm o-ring
1x 1.9mm o-ring

Compatible with 14mm threads