Petzl Knee Ascent Ascender Loop AssemblyKnee Ascender Assembly With Foot Loop To Facilitate Ascents On A Single Rope, For Tree Care Petzls KNEE ASCENT LOOP assembly facilitates the arborist's ascent when using the ZIGZAG or ZIGZAG PLUS mechanical Prusik on a single rope. It contains an upper strap, a CROLL L rope clamp, a lower strap with foot loop and an XS size TOOLBAG tool pouch. The system is entirely adjustable and adapts to all shapes and sizes. Features: Facilitates ascents on a