The Enhanced Lower parts kit offers a convenient upgrade package for the AR15 for those looking for a complete Strike Industries solution for new builds, or to update their plain jane AR. This kit includes all the basics that you will need to build out your AR (minus grip), but with Strike Industries Enhanced lower parts where applicable. This complete kit includes our fire control group which offers a crisp 4.5 to 5.5 lb pull, with unmatched smoothness for Mil-Spec style AR15 triggers. Longitudinally ground and polished sear engagement surfaces coupled with precision cut sear angle equate a vastly improved trigger feel without sacrificing safety or reliability. Features: Includes SI's signature enhanced lower parts (AR-EBC, New improved SI-SMC, AR-EPTP, and AR-HS-60/90-3in1) SI's trigger springs provide a consistent 4.5 to 5.5 lb trigger pull with our fire control group