This is an adapter to install an AR15 collapsible stock and pistol grip on to the receiver of a Remington 870 shotgun. It is a Mesa Tactical low mount, so a rail is not necessary. Pistol grip included but you'll need to supply the stock of your choice.
Used, very good condition. Asking $85.00 shipped.
I can't believe no one has grabbed this up.
C'mon , your chiropractor needs to make a living too. heh heh