All the parts you need to get started on your next AR15 build in convenient color-coded packets to simplify assembly.Features :Bolt catch/roll pinBolt catch plunger/springTrigger guard/roll pinTrigger, Trigger springDisconnector, Disconnector springHammer, Hammer springTrigger/hammer retaining pinsAmbi-Safety, detent, & springMagazine catch, spring, & release button