These are open face bolts.

This bolt is made from a nylon-like material that is lighter but stronger and more durable than delrin. It will not swell or shrink with temperature change. This bolt has a cupped face and great air flow. NO oil needed. This bolt comes with ball bearing and spring system. Choose with or without O Rings. Each bolt is hand made here in the USA, and comes with a Bandit stainless steel push pull pin.