Description: Ideal for Arborist rigging where three independent tie-ins are required. One orange, one black anodized aluminum sideplates, 1 1/4" aluminum sheave, bronze bushing, and aluminum axle. The new CMI Tri Tie pulley is built to work. The anodized side plates are made of 7075-T6 aluminum. 7000 series alloys are some of the highest rated strength alloys available today and are used in high performance applications.