Looks can be deceiving, but this slim, replica 6x35mm magazine fits most M4 variants. Though intended for replicas of the Knight's Armament Co. Personal Defense Weapon, these look great in nearly any M4 build. Their slim design and negligible weight make them ideal for compact or high-speed loadouts, or just keeping some unobtrusive backup magazines handy.
These will fit most KWA, VFC, Krytac, G&G, and Echo1 guns designed to take M4 magazines. However, they do not fit well in the VFC 416 or Classic Army SCAR series of rifles.