Belay device with cam-assisted blocking, optimized for lead climbing Take your belay game to the next level. NEOX is an assisted blocking belay device for the gym and the crag. Ideal for lead climbing, it has an integrated wheel that allows you to smoothly and quickly pay out slack to the climber. Its ergonomic handle provides comfortable descent control. It can be used with single ropes from 8.5 to 11 mm. Not into the Neox? We also have the Petzl GriGri and Petzl GriGri+.