CAMP HMS 3 Lock
Here's what other sites are saying:
With three actions to open it, the Camp USA HMS 3Lock Carabiner is one of the safest choices for climbing, whether you're belaying or rappelling. Slide the locker up, twist it clockwise, and pull it open. The keylock nose eliminates snagging your rope.
The CAMP HMS Lock is a large screw gate carabiner designed for belaying and rappelling with either a Munter hitch or standard belay device. Keylocking closure eliminates snagging.