Individually tested and fully CE rated the Petzl Am'D Ball-lock is designed specifically for attaching mechanical devices eg Petzl ZigZag. The large gate opening makes it easier to clip in; asymmetrical D-shape helps keep the proper orientation on working axis when loaded. The Ball-lock auto-locking system requires three different actions to open the carabiner (push the green button - turn - open the gate) which is essential for arborist work but these three actions can easily be completed with one hand. Excellent strength-to-weight ratio. Major axis strength 28 kN, gate open 8 kN and the minor axis 7 kN. Made in the USA from 7000 series aluminum. Individually tested.