The Fusion Steel D Screw Locking Carabiner is extra large perfect for a trolley back-up. Spring loaded gate with screw lock, this can be used as a regular carabiner or used as a back-up because of its super sturdy steel design.
Use the Steel D Screw 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. Works great used with two lanyards that tie into the harness.