The 7.62x51 NATO (.308 Winchester) PMAG 25 M118 LR/SR GEN M3 Window is now compatible with M118 LR ammunition with a max OAL of 2.830". This is a lightweight, cost effective, high reliability magazine for SR25/M110 pattern rifles featuring true 25-round capacity, constant-curve body, anti-tilt follower, snap on Impact/Dust Cover, and features transparent windows to allow rapid visual identification of approximate number of rounds remaining. Please note that this increased length capacity means that the PMAG® 25 M118 LR/SR GEN M3 Window may or may not drop free from some models of weapons. However it can still be pulled free.”
AR-15, Issue:11, Page:061
Big Book Catalog, Issue:72, Page:069