Magpul's M3 polymer technology and manufacturing processes for enhanced strength, durability, and reliability to exceed rigorous military performance specifications. The over-insertion stop on the spine helps ensure that the magazine will not over-insert on compatible weapons. USGI-spec stainless steel spring for corrosion resistance and field compatibility. Aggressive non slip texture at the front and rear for superior grip. Paint pen dot matrix to increase durability of magazine identification. Strong, slim floorplate design that retains positive magazine handling and easy disassembly.NoteCompatible only with the new SIX8 model rifles. They will not function in older 6.8mm rifles or any other manufacturer's rifles.