Petzl Reverso 3 Belay and Rappel Device Green, One Size Ultra light (77g), multi-purpose belay/rappel device, with range of friction adapted to different ro For use on single ropes (Min. 8.9 mm), half and twin ropes (Min. 7.5 mm) V-shaped friction channels: increased friction on thin ropes; Friction is adapted for larger diameter ropes, Increased holding power in Reverso mode Asymmetrically grooved sidewalls. Increased braking power during a leader or top rope fall or while rappelling. Rope smoothly slides through device when taking up slack Rope friendly: will not kink the ropes regardless of the mode used; Separates the two strands of rope when belaying and rappelling