XTS AR-15 Lower Small Parts Kit Black. Whether you're restoring an old firearm or looking to build one from the ground up the XTS AR-15 Lower Parts Kit has all the parts necessary for assembly. The XTS AR-15 Bottom Bolt Parts Kit even includes hard to find but highly needed Bolt Catch Spring Bolt Keeper and Broken Axle Screw. By utilizing this XTS weapon building block kit builders can now easily restore or build a working lower receiver. Specifications for XTS AR-15 Lower Small Parts Kit: Manufacturer: XTS Color: Black Gun Model: AR-15 Country of Origin: USA Package Contents: XTS AR-15 Lower Small Parts Kit XTS AR-KIT: AR-15 Lower Small Parts Kit Black