When the Rescue Hauler (SK-710) is used with the matching double 3″ pulley (SK-711 or SK-712), it gives you a 4:1 mechanical advantage. Both products are anodized red in color with one black sideplate for those who want color coding to describe rigging techniques. Even the pulley sheaves are anodized to meet a 200-hour salt spray test for use in a marine environment. The cam is guaranteed for life. If you wear one out, we will replace it free. The 3″ pulleys are kinder to the rope and they prevent the rope from rubbing on the frame, which creates unnecessary friction. The frame of the Rescue Hauler is machined from extruded aircraft aluminum. This product is truly superior to all similar devices.