Purple grigri. 9 to 10. It is equipped with an ergonomic handle that provides a smooth and comfortable descent for the climber. 5-11mm dynamic single rope diameters. The engineers over at Petzl must never be satisfied, because while the Grigri is already a best-seller, and perhaps the most popular assisted braking belay device on the market, the Grigri + Belay Device offers a smoother, safer performance than its predecessors. It can be used with all single ropes (optimized for 8. 5–11 mm). GRIGRI + is an assisted braking device designed for all climbers, for both indoor and outdoor climbing. . Designed for lead and top rope climbing, GRIGRI is the gold standard for belay devices. The reduction handle offers exceptional descent control.