PETZL WILLIAM TRI-ACT HMS CARABINER

Like the other reviewer, I find it hard to open onehanded without practice - The twistlock is designed funky, where the top part will clear the hook, yet the bottom will not clear the hinge without another 1mm or so of twist. Could easily fix it with a file, but rather not. At the widest point, across spine to hook, is 3" wide. Height is a little over 4" tall. About 1" of space on the inside at the bottom, and 2" inside across the top.

I find the gate very hard to open with one hand. Obviously the intent is to ensure it doesn't open randomly but I find I need two hands to operate the gate.