The WorkSAFEGEAR Rocker is a simple design which operates by camming action from an offset attachment point. It also runs freely both ways on the rope, although it has a small lug which can be rotated into position to give friction on the rope should this be required. This can also be used to "park" the device at a particular level if required. The Rocker is certified to EN 353-2 for fall-arrest devices.