Vltor A5 Stock Combo Kit. 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. Specifications for Vltor A5 Stock Combo Kit: Manufacturer: VLTOR Gun Type: Rifle Condition: New Buffer Tube Size: Mil-Spec Fabric/Material: Polymer Vltor A5 Stock Combo Kit 24Y-BSC-ASCK 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 Package Contents: Vltor A5 Stock Combo Kit 24Y-BSC-ASCK VLTOR A5H2 buffer weighing 5.3oz Rifle spring Seven position receiver extension Lock plate Lock nut VLTOR EMOD stock What firearm models does the manufacturer say Vltor A5 Stock Combo Kit is compatible with? The manufacturer says that Vltor A5 Stock Combo Kit is compatible with AR-15