Carabiner Pearlock Screwgate. Black Diamond Pearlock Screwgate Carabiner. With an updated modern design blended seamlessly with a hot-forged utilitarian shape, the PearLock features a large rope-bearing surface, making it ultra-smooth for belaying, using a munter hitch, or as the brake carabiner with an ATC Guide. The classic screwlock sleeve rounds the PearLock out (pun intended) to make this carabiner an ultra-versatile workhorse.