The William is the latest and largest addition to Petzl Charlet's carabiner lineup. It isespecially suited for belaying and optimal use of the Munter hitch, even with double ropes, thanks to its' wide size. The William encorporates the Keylock system which eliminates the notch in the carabiner nose, helping to prevent it from snagging on ropes, webbing and anchors. The Ball Lock version is auto locking, making it the most fail safe of the available locking mechanisms. A green ball must be pushed in while the gate is being rotated to unlock the carabiner. Finger grooves in the sleeve make one handed operation possible. Two other locking mechanisms are available: Screwlock manual locking and Spinball rapid action manual locking.