The VLTOR A5 Stock Combo Kit is not just an EMOD stock with M4 components; it was developed as a completely new operating system. Specifically developed on the request of the USMC, the A5 combo kit is considered to be the most innovative upgrade for the AR platform, increasing the reliability, accuracy and performance of any weapon. Brings down cyclic rate of M4 carbines Lowers bolt carrier velocity Improves reliability and accuracy Reduces felt recoil Waterproof side battery compartments that holds 4 CR123 or three AA batteries in each compartment Weatherproof compartment in the clubfoot area of the stock that hold two AA batteries Comes pre-assembled with rubber buttpad and strike plate Matte (anti-reflection/anti-glare) finish Impact and temperature resistant polymer, specifically blended for VLTOR stocks Has standard military and quick disconnect swivel socket accessible from both sides Slightly wider and longer at the toe than a regular M4 stock with a noticeable negative pitch making transitions from the ready position feel more natural. Seven position Mil-Spec impact extruded receiver extension specifically used for the A5 system Kit includes: VLTOR A5H2 buffer weighing 5.3oz and rifle spring, seven position receiver extension, lock plate, lock nut and VLTOR EMOD stock Weight: 1 lb 10.7 oz (complete kit and all mounting hardware)