This is a Gearhead Works Stock Kit known as the Tailhook MOD 1, model GHW-38.
The Patented Tailhook MOD 1 is the most compact pistol brace in the world. At less than an inch thick" it can be adapted to practically every platform on the market. To activate the brace functionality" depress the release button and pull the arm down. This creates the shelf that will counterbalance the muzzle weight of your large frame handgun. The ability of your forearm to hold the weight allows you to relax your shooting wrist and concentrate on trigger control. True one handed operation is achieved since you do not need a second hand to attach the brace to your arm. MOD 1 can be set up for right or left handed operation.
Features:
Machined from billet aluminum
Clamps to pistol buffer tubes or adapters from 1.17 to 1.2 in diameter
Built-in limited-rotation sling swivel QD socket
Hard-anodized finish
Weighs 4.5 oz