Circle 10 AK and Manticore Arms have collaborated to bring the new AK Flush Fit Side Fold Adapter to market. You may remember the sneak preview of this adapter from a few weeks ago.
This AK Flush Fit Side Fold Adapter is designed to be used with the 4.5mm side folding trunnions commonly found on Bulgarian AKs (it is not for converting fixed stock AKs). It is for use with mil-spec diameter stocks and the end of the adapter features a threaded cap for storage. The innovation here is the relief cut in the side of the tube that allows it to fold against the receiver, covering the optic rail.
Check out the Circle 10 AK website for more details and to purchase.