DMM Belay Master Locking Screw Gate Carabiner
Carabiners don�۪t always behave as you might want them to. There is potential for the biner to flip into a bad alignment and for cross loading to occur.
The Belay Master features a special clip that once locked in position prevents cross loading occurring by holding the biner and belay device in the correct alignment. There is another advantage too: the clip can only be locked if the Screwgate has been properly closed first.
It also has the Taper Lock nose, a special flared profile on the nose of the biner which significantly increases the side loading strength of the gate. The belay Master 2 is also surprisingly light.
From a tree climbing perspective, it's an excelent attachment carabiner for your footlocking strop, where a lot of movement of the attachment carabiner is occuring.