The PMAG 30 GEN M3 Window is a 30 RND 5.56 NATO polymer magazine for M series compatible. This magazine features a long-life USGI-SPEC stainless steel spring, four-way anti-tilt follower and constant curve internal geometry for reliable feeding. A redesigned bolt catch notch in the rear of the magazine provides increased bolt catch clearance, while an over-travel stop on the spine helps ensure the magazine will not over-insert on compatible weapons.