This is a F.A.B. Magazine known as the ULTIMAG chambered in 223 Remington, model FXUMAG30T.
The Ultimag 30R is a 30-round 5.56x45 NATO (.223 Remington) polymer magazine for AR15/M4 compatible weapons" with transparent windows for rapid visual identification of remaining rounds.
Features:
Ergonomic design
Enhanced grip
Faster magazine change
