Petzl Knee Ascent Loop (D022DA00)Petzl Knee Ascent Loop (D022DA00) Knee ascender assembly with foot loop to facilitate ascents on a single rope, for tree care The 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.