Simple, lightweight and smooth feeding, the ATC belay/rappel device is easy to operate and, when used correctly, won’t kink your rope. Designed for 7.7-11 mm cords and to hold falls more easily, its extensive surface area dissipates heat effectively when lowering or rappelling. Black Diamond - ATC Simple lightweight and smooth feeding the ATC belay rappel device is easy to operate and when used correctly won t kink your rope Designed for 7 7 11 mm cords and to hold falls more easily its extensive surface area dissipates heat effectively when lowering or rappelling