A PolarStar Hop Up Thing thing The UGS is installed into

The UGS is installed into the VFC HK417 in the same manner as the original buffer tube by threading into the receiver

Includes delrin spacer with steel nut

it is easily replaceable

CO2 Cartridges & HP Spring Not Included

It also has a microswitch on the back which interfaces with the rifle's selector controls

A PolarStar Hop Up Thing thing The UGS is installed intoPolarStar Hop Up Thing Bet 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