Includes all the little parts that get lost or need replacement during your builds. Keep a set on hand for friends and emergencies.Features :(1) Buffer Retainer, (4) Takedown/Pivot Detent (2) Selector Detent (2) Selector/Ejector Detent Spring, (2) Disconnector Spring(6) Takedown/Pivot Pin Detent Spring (1) Buffer Retainer Spring (2) Bolt Catch Spring(1) Bolt Catch DetentAll Components Manufactured in the USA