This is the Taurus TX9 Full Size 9mm 19-round extended magazine. 

Maximize your Taurus TX9’s capacity with this high-quality factory extended magazine!

Constructed from high-quality steel and featuring an anti-tilt polymer follower, this magazine delivers superior durability and reliability. Taurus also included a lightweight, removable polymer baseplate for easy maintenance, so you can keep your magazine in perfect condition.

Rear-facing witness holes allow you to keep track of your remaining rounds, leaving virtually nothing to be desired from these high-capacity magazines! 

Throw a couple of these 19-round extended magazines in your cart before you forget!