This Rail Kit uses M-LOK interface and QD sling swivel sockets. The goal was to make a low profile rail that could hold a lot of weight.
Rails come in 8.6", 10.5", 13.5", and 15" lengths, and weighs 5.9 - 10.5 oz. It is 1.54" wide outside, 1.35: inside.
The kit also comes with 416R QD sling swivel, shield panel
Price ranges from $259.95 to $284.95
From: Griffin Armament