Makes it easy to advance your grip when hauling in the sheet. The perfect combination of control and convenience.. Ø5 mm Delrin ball bearings and Ø45 mm carbon fibre reinforced polyetherimide sheave. The sheave automatically changes from free-turning to ratchet when the load increases. The sailor decides when the automatic ratchet kicks in. The switch-over point is set using an allen key to adjust a screw inside the sheave. Fast, simple, precise. Max line size 8 mm.