This is a Nordic Components narrow diameter free float tube with an adapter that allows the use of the factory M&P 15-22 barrel nut. A friend with a machine shop made the adapter for me, and installed it into the tube. The first two holes in each row are threaded 10-32. I tapped two on the left hand side with the same thread.

I'm asking $80 shipped. USPS Money Orders or PayPal. Located in Arkansas.