Used Black Diamond ATC-XP Belay Device The ATC-XP is the next evolution of Black Diamond’s ‘Air Traffic Controller’, tubular belay device. With great holding and stopping power and a versatile design that accepts a wide range of ropes, this classic belay device is ready for a variety of missions. High-friction mode offers 3 times greater hold and stopping power than regular friction mode Machined windows through device for weight savings Durable cable holds its shape and resists getting caught up between ropes Versatile design accepts ropes from 7.7 to 11mm