Midwest Industries Rear Sling Mount Adapter Ambidextrous Loop AR-15 Carbine Aluminum Matte

From MidwayUSA

These aluminum adaptors work very well in all types of sling configurations single point, two point or three point tactical slings. Each adapter is ambidextrous for right or left hand operation and there is no removal of the buffer tube or special tools required. To install simply pull down on the adjustment lever of either a four or six position stock until the pin is disengaged enough to slide the whole plastic portion of the stock completely off to the rear, then slide on the adapter tighten one screw and install the stock in the reverse order and you're done in about two minutes