TWIST cables are memory-free! They consist of a multi-strand, steel cable coated with red nylon. This 8" (20 cm) length will make a 16" (40 cm) circular when 4" (10 cm) tips are attached. Lifeline holes can be found at each end of these cables. Insert the T-shaped tightening key into the lifeline hole to assist with securing your tip/cable connection. For sizes US9 (5.5 mm) to US15 (10 mm)