The TAPCO AR-15 Lower Parts Kit has all the pieces needed to assemble a lower receiver with parts made from quality steel. The pieces in the TAPCO Lower Parts Kit are highly wear-resistant and are able to withstand the wear and tear of continuous shooting. Many of the parts in the TAPCO Lower Parts kit feature a black phosphate finish that provides corrosion protection from extended shooting. Includes: Takedown/Pivot Pin Detents (2) Bolt Catch Spring (1) Safety Detent Pin (1) Bolt Catch Plunger (1) Bolt Catch Roll Pin (1) Buffer Retention Pin (1) Trigger Pins 5.56 (2) Safety Detent Spring (1) Spring for Buffer Retainer 5.56 (1) Springs for Takedown/Pivot Detents 5.56 (2) Spring for Mag Catch (1) Bolt Catch (1) Safety Selector 5.56 (1) Magazine Catch Button 5.56 (1) Magazine Catch 5.56 (1) Pin for Receiver Pivot 5.56 (1) Pin for Receiver Takedown 5.56 (1)