This is a Magpul Industries Magazine Accessory known as the Ranger Floorplate chambered in 223 Remington, model MAG212-BLK.
The Magpul PMAG Ranger Plate is a floorplate replacement for the 5.56x45 PMAG 30 AR/M4 GEN M2 MOE" PMAG 30G" and EMAG(TM) that incorporates an integral loop similar to the original Magpul USGI Ranger. When installed on the base of the magazine" the PMAG Ranger Plate provides unsurpassed speed and control during high stress" tactical magazine changes. NOTE: This Ranger Plate is a dedicated fit for 5.56x45 AR/M4 GEN M2 MOE PMAGS as well as the EMAG and PMAG 30G MagLevel. Will NOT fit PMAG GEN M3 magazines" 7.62x39 PMAGS" 7.62x51 PMAGS" or any metal magazine.
Features:
Dedicated fit for 5.56x45 AR15/M4 GEN 2 MOE PMAGS, EMAG, PMAG 30G MagLevel