I have other UTG stuf that is great. I got this at the same time as an Aero upper. Either the Aero BAR nut or this wrench is off by Nearly 1/8". This chingadaras is way way over size for the castle nut and muzzle device. Didn't send it back because my oldest son thinks the peace sign is cool, and , ya know, that's whats important. This thang really irritates me.