The CMI Aluminum Arborist Rigging Block (1" Rope) is a giant abrorist rigging block designed for the beefest ropes. Inside it has aluminum wheels with stainless steel axels. Outside it has blue anodized aluminum sideplates. It can handle 1" rope capacity and a good safe working load of 13,600 and minimum breaking strength of 68,000 lbs. It is sturdy but not too heavy.