You can find the Magpul PMAG 30 MOE Window 5.56 Magazine here.

The Magpul PMAG 30 AR/M4 MOE Window Magazine features the same impact and crush-resistant polymer construction as the MOE but has the addition of durable dual-side transparent windows for quick determination of the rounds remaining in the magazine. The addition of a high visibility indicator coil on the spring and numerical markers on the magazine body aid in verifying remaining rounds in the magazine. The MOE Window also has a stainless steel spring for corrosion resistance, and anti-tilt, self-lubricating follower for increased reliability. The PMAG MOE Window has a textured gripping surface and flared floorplate for easy handling.

Caliber: 5.56
Capacity: 30 Rounds
Color: Black