Ultra lightweight multi-purpose belay/rappel device The multi-purpose, lightweight REVERSO is a belay/rappel device designed for belaying and rappelling. Reverso mode allows independent and simultaneous belaying of one or two seconding climbers. It is compatible with most rope diameters: single ropes 8.5 to 10.5 mm, half ropes 7.1 to 9.2 mm, and twin ropes 6.9 to 9.2 mm.