Whopie Sling 3/4″x 4-11′. This Adjustable Sling can be adjusted from short to long in just seconds and is often used by riggers to anchor a block or friction device to a tree. The Adjustable Sling allows the rigger to mount hardware snug against the tree, minimizing slack in the rigging system. Each sling is spliced by the experts at AT-Height using durable Samson Tenex Tec, 22,300 lb. minimum breaking strength.