The Defender-H lower receiver, previously known as the original .308 Modular Weapon System (MWS®) lower receiver, features an ambidextrous selector and magazine
release machined directly into the receiver. This lower
receiver includes a 2 stage Axle trigger group, LMT grip, QD endplate, and
MARS-H and Defender-H lower receivers are only guaranteed compatible
with LMT upper receivers. Other brands may not fit or function correctly.