Description of Black Diamond ATC-XP Belay Device A true variable-friction device, the ATC-XP maintains the silky-smooth feeding of the ATC but ups the braking power. For belaying and rappelling with 7.7-11 mm ropes, it’s designed with a smooth, low-friction side and a high-friction side with v-shaped grooves for three times more friction. An extended central web keeps biners and ropes properly oriented and helps reduce kinking. Features: Weight: 89 g (3.1 oz) Blue Denim color Silky-smooth feeding of ATC Better braking power igh friction sides has V-shaped grooves for 3 times more friction Extended central web