The Fusion Steel D Quick Lock Carabiner is perfect for a trolley back-up. It can be used as a regular carabiner or used as a back-up because of its super sturdy steel design.
Use the Steel D Auto Lock Carabiner as an over-the-trolley back-up to prevent injury in case of zip line trolley failure. The all-steel design ensures that if the carabiner runs along the zip line cable, it will not be damaged and will maintain integrity for years.