This is a factory Taurus TX22 .22LR 16 Round Magazine. 

This genuine Taurus TX22 magazine delivers superior reliability in a lightweight and durable package. Inside the polymer body is a high-quality steel spring and anti-tilt follower that work together to deliver a smooth operating experience. 

A welcomed bonus feature is the side-facing load-assist lever that makes loading the magazine quick and easy. The load-assist channel doubles as a witness window to keep track of how many rounds you have left.

To top it all off, you can rest easy knowing that it has met or exceeded all of the Taurus factory specifications and tolerances. If you enjoy spending your weekend plinking away with your TX22, save some time at the range by loading several of these magazines at home before heading out. 

With .22LR ammo being so affordable, you can spend some of that money you saved to pick up a few more magazines! 

Here is some information about the Taurus TX22 Pistol

The TX22 is engineered to deliver best-in-class accuracy and reliability, this rimfire polymer sporting pistol shoots and feels every bit like a custom-tuned competition model without any costly upgrades or modifications. From the short, smooth pull of its precision-designed Taurus Pittman Trigger System (PTS) to the built-in comfort of its ergonomic grip, the TX22 is one performance-driven full-size that’s ready to race. Right out of the box.