The Magpul MagLink coupler for PMAG 30 and 40 round AR/M4 magazines* which allows the user to attach two magazines together for more efficient speed reloads, and to keep additional ammunition accessible on the weapon at all times. The MagLink features a two-piece bolt on design and durable, lightweight reinforced polymer construction. Made in U.S.A. Fits 5.56x45 PMAG 30 and 40 round AR/M4 GEN M2 MOE and AR/M4 GEN M3 magazines Impact resistant polymer Wide-set, two-piece bolt-on design Integral grooves interface with PMAG ribbing *NOTE: This MagLink is NOT compatible with first generation PMAGs (with Black follower, circa 2007-2009), 10 or 20 round PMAGs, custom branded PMAGs, or any other non AR15/M4 specific Magpul magazine such as the EMAG, PMAG 30G, or PMAG 30 AUS. Will also not fit other larger caliber magazines such as 7.62x39 and 7.62x51 PMAGS or any metal magazine.