This adapter works with a modified factory old style Gen 1 Kriss folding cheek rest. There is a newer style stock with a different cheek rest recently released. The hole for the adapter is too small on the new style Gen 2 folding arm. This adapter works with the early style setup before 2017. It requires modification of the cheek rest arm.
First step is to remove the butt stock portion by loosening the set screws. Discard that part to avoid constructive intent.
The lower receptacle needs to be cut off and filed smooth leaving only the top one.
Insert the adapter and drill for a pin.
A video tutorial is on our Youtube channel for the installation process. Please review this prior to ordering so you understand the process and are capable.