A very unique assisted-braking resistor device from Edelrid.  Designed to assist a belayer that is significantly lighter in weight than the leader.  The Ohm works by increasing the rope friction in the system, reducing the force being transmitted to the belayer, and allowing a lighter belayer to more easily hold a heavier climber. The Ohm can be carried just like the first quickdraw on your harness, pre-rigged with the lead rope already installed, and be ready to just clip the entire set-up to the first bolt off of the belay. This is not a belay device.  The belayer still uses their own regular belay device to belay the lead climber as they would normally.