The Am'd or American D is Petzl's midsize D shaped locking carabiner. It utilizes the Keylock system which eliminates the notch in the carabiner nose, helping to prevent 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. Strengths: Open: 8kN Closed: 28kN Weight: 74g Note that this item of climbing safety equipment is non returnable. Please call us toll free at 877 236 8428 or e mail bentgatebentgate.com with any questions.