The Strike Industries Enhanced Lower Receiver Parts Less Trigger, Hammer and Disconnector includes most of the necessary parts to build (or enhance/upgrade) a lower receiver minus the trigger group, pistol grip and trigger guard for those lowers that don’t have one built-in. This kit includes all the basics that you will need to build out a new lower and a perfect pairing with the many various style SI AR Grips available. Reuse an existing AR trigger group or the freedom to pick your own AR trigger you rather have and not get stuck with a plane jane Mil-Spec trigger will just collect dust in a drawer somewhere. However, the hammer and trigger springs along with pins are included in the bag. The Strike Industries AR-10 Enhanced Lower Receiver Parts Trigger, Hammer and Disconnector includes SI signature enhanced lower parts like the bolt catch, magazine release, pivot/takedown pins and HEX Selector Switch that offers both a 60 or 90-degree angles 3 in1 combo, no other lower parts kit (LPK) on the market gives you the most bang for your buck.