Compatible with all rope types, the Air Force 3 allows the leader, when at the stance, to individually belay and lock off one or two seconds. The small insert hole allows the rope to be released even when under tension. The Air Force 3 belay device is compatible with single ropes of any diameter but is specifically designed for use with half and twin ropes. The V-grooves offer extra friction to improve rope braking while belaying and optimum energy absorption when catching a leader´s fall, yet provide enough smoothness to pay out slack easily. The wide, straight grooves offer edge-free running of the rope.