The rockO is a blend of the traditional oval and the rockD giving it more strength than the standard oval

99 RockD Autolock

What is the difference between the CL-3504C and CL-3502C

the core to pull through the entire knot

5/8" WHOOPIE SLING Select a Size:5/8 Diameter The rockO is a blendWhoopie slings feature an adjustable eye and a stationary eye that allow for an exact fit around the base of the tree or rigging point while aloft. Once the whoopie sling is tensioned it remains snug for reliability. Whoopie slings work great for anchoring a lowering device or for attaching blocks while rigging. Color indicates sling diameter. 1 2" diameter (Blue): adjusts 2. 5' 4' 5 8" diameter (Red): adjusts 3' 5' 3 4" diameter (Orange): adjusts 3.