This Railed Stock Adapter was designed to replace the sling loop on the NAK-9 pistol and allow the installation of stocks on an approved SBR.
It can also be installed on most AK pistols by simply drilling and tapping your rear trunnion.
8.5mm drill size for tap
It has a lip on the bottom that prevents it from rotating when installed.
Note that installing a stock on a pistol makes it an SBR, make sure to follow all local, state and federal laws!