Quite simply, Ronstan Ratchet Orbit Blocks™ have the highest holding power available. The sophisticated NC-machined sheave features Generation 2 of our patented sheave cross-hole geometry. Its holding power is up to 20:1, almost double that of our nearest competitior. The unique sheave design has 12 gripping faces which directly resist loaded line movement. Traditional designes have only 8 faces with an angled resistance to line movement. Our Generation 2 design has straight resistance faces which both distribute the load and minimise rope wear. These faces are offset from the radial line, to draw the rope down into the gripping area when under load.  Sheave Ø 55 + 35 mm Max. Rope Ø 3/8 mm Max. Cable Ø mm Pin Ø 5 mm M.W.L. 250 kg B. L. 750 kg Weight 112 g