Design and Details Specifically contoured for operation with one hand. The locking mechanism for opening and closing allows the rope to be inserted without removing the device from the anchor and it cannot be opened when the pulley is loaded to prevent accidental openings during use. Toothed cam is designed for an immediate and strong grab on ropes from 8 to 13 mm. The cam is enabled and disabled with a switch that is protected inside the flanges to prevent accidental activations. One movement to open the cam for easier insertion or removal of the rope or to use the device as a non-locking simple pulley. Two movements to enable the cam. The two attachment points (main attachment point and the becket hole) allow for the rotation of carabiners for maximum ease of use. Large diameter sheave with sealed ball bearings for very high efficiency (95%). Robust construction features hot forged side plates, precision milled aluminum alloy sheave, and stainless steel cam, rivets and pins.