This is a Gearhead Works Adapter known as the Scorpion, model GHW-39.
This adapter allows the user to mount the Patented Tailhook Mod 1 brace to the factory CZ folding cheek rest. It is injection molded reinforced polymer and can be installed to your choice of 3 positions. Features anti rattle tensioner and contoured to blend the two parts together
Features:
Polymer construction
Adapts CZ Scorpion cheek rest to Tailhook Mod 1