Polarstar HopUp Unit - Black M4Bet you cant guess what this Thing is for. Its a hop up, or a paperweight, or maybe a very expensive fidget spinner, but were pretty sure its a hop up. Actually, it's a 6061 T6 Aircraft Aluminum hop up. We know, "Aircraft Grade" is the favorite buzzword of every airsoft company trying to make a $15 part sound like it belongs on a SpaceX rocket. But we actually machine these Things in house at PolarStar to + 0. 002" tolerances because were tired of