This is a Magpul Industries Magazine known as the M3 chambered in 223 Remington, model MAG560-BLK.
The next-generation PMAG 20 GEN M3 is a 20-round 5.56x45 NATO (.223 Remington) polymer magazine for AR15/M4 compatible weapons. Along with expanded feature set and compatibility" the GEN M3 incorporates new material technology and manufacturing processes for enhanced strength" durability" and reliability to exceed rigorous military performance specifications. While the GEN M3 is optimized for Colt-spec AR15/M4 platforms" modified internal and external geometry also permits operation with a range of additional weapons such as the HK(R) 416/MR556A1/M27 IAR" British SA-80" FN(R) SCAR(TM) MK 16/16S" and others.
Features:
20RD capacity
Polymer construction
Anti-tilt, self-lubricating follower
Ribbed gripping surface
Flared floorplate
Over-travel insertion stop