This is the factory Glock 19-round magazine in coyote brown, the one that ships in the G19X. It is a standard full-size G17 body with Glock's factory plus-two floorplate, so the capacity goes from the usual 17 to 19 rounds of 9mm without an aftermarket extension. For a USPSA Carry Optics or Production shooter on a full-size Glock, two extra rounds in a factory magazine can be the difference between a stage that runs clean and one that needs an extra reload.
Construction is the Glock standard: a hardened steel insert wrapped in polymer, which is the design that lets these magazines survive being dropped loaded onto concrete during a reload. The spring and follower are factory Glock, so feeding matches what the gun was built around.
A couple of things to know. The coyote brown is a color choice, not a performance feature, so if color coding your match magazines does not matter to you, the black version of the same magazine does the identical job. And capacity rules vary by division, so confirm that a 19-round magazine is legal for your division and that it does not bump you over a capacity limit before you load a set for a match.