Circle 10 AK and Manticore Arms have teamed up to design the Circle 10 AK/ Manticore Arms Flush Fit side fold adapter. This unit fits side folding trunnions with 4.5mm pins, usually found on side folding Bulgarian AK74s. The tube has a cut out that permits adjustable AR15 stocks to be folded flat against the side of the receiver, OVER your side mount optics rail. Tube is MILSPEC diameter, and comes with a storage compartment which is sealed by a screw in cap. Price is $139.95.