This PRO mobile rope grab features a mobile design that allows hands-free operation by following the user along their lifeline. The stainless steel and aluminum build resists corrosion in harsh conditions and features a sophisticated fall-arrest system with multiple failsafe to ensure the worker is safe in the event of a fall. Fits around 5/8" (16 mm) diameter polyester/polypropylene rope lifelines, and works best with 3 ft (0.9 m) shock-absorbing lanyards.