Yes it works. Yes, you can belay. And rappel. But I disagree that it is just like the Black Diamond ATC. Loading the belay device is not smooth. Rappelling on the Shell device is not at all fast. Good luck lowering a climber who weighs less than 140 pounds. The belay device puts too much friction on the rope, preventing the rope from running smoothly. Finally, I'm concerned that the exposure of the wire loop (see below) could pose a significant issue for the integrity of your rope. Spend the extra Lincoln, and you won't have to purchase a replacement.