Tacfire LPK-USA-SS: This parts kit contains everything required to build an AR-15 lower receiver minus the stock assembly. From the stainless steel hammer and trigger to the pistol grip and trigger assembly, you will be able to complete your AR-15 rifle build to your specifications and style! Whether this is your first build or the 50th, this lower parts kit will meet your needs. Tacfire builds quality AR-15 parts and accessories that are built to last a lifetime. This model also features the enhanced stainless steel trigger and hammer, which adds longevity and reliability to your build!