The PlumCrazy lower features an all-polymer construction to create a lightweight and inexpensive receiver with similar strength and corrosion resistance to traditional aluminum receivers. The Gen II receiver features a reinforced buffer tube interface to address the increased stresses accumulated in the area under heavy use. This receiver features a standard AR-15 design and is compatible with standard AR-15 magazines. The receiver is complete and includes a pistol grip, polymer buffer tube assembly with the buffer and spring, trigger assembly, and lower parts kit pre-installed.