The Petzl Micrograb is designed for ropes with diameters from 7/16" - 1/2". It is crafted from aluminum and has a fixed cam so it can not come loose once it is installed. Adjustable lanyard clamps are mainly used in hauling systems and to build adjustable lanyards. Cam-loaded clamps apply the load directly to the cam so that they will engage even if the rope is muddy, wet, or icy.