The ATC-Guide is Black Diamond's most versatile belay/rappel device thanks to its smooth and grooved sides, plus a "guide mode" for bringing up one or two seconding climbers with ease and control. Often imitated, but never equalled, the ATC-Guide is a burly, super-functional, year-round belay/rappel zen master.Regular friction mode for belay and rappel. High friction mode (3 X the friction!) for belay/rappel. Beefy cable holds its shape and resists getting caught up. Guide mode works with one or two climbers ascending and descending. Dependable and smooth operation in all conditions. Deftly handles ropes from 7.7 to 11 mm.