Every part you need to assemble your bare lower receiver into a functional piece for your custom KP-15 Polymer Receiver build. This is KE Arms premium Lower Parts Kit complete with black oxide springs. All parts Made in USA.Features :Parts Included:- Trigger & Spring- Hammer & Spring- Disconnector & Spring- Trigger Pin- KP-15 Hammer Pin- KP-15 Optimize Safety Selector Switch- Selector Detent Spring