This is the Magpul PMAG 17 GL9 9mm 17-round magazine for G17 pistols.

Featuring an advanced polymer construction, this PMAG 17 is lightweight and durable for Glock 17 pistol owners. Magpul’s take on the magazine is feature-rich: high-vis orange follower, anti-tilt follower, stainless spring, round indicator at round 17, and durable polymer base pad.

This PMAG holds up to 17 rounds of 9mm ammunition – the same capacity as factory Glock 17 magazines. In addition, the flared base pad features a pin-point dot matrix. It’s excellent for marking the bottom of the mag for easy identification.