The Harken Classic sailing dinghy block is designed for 10mm rope with twin double plastic sheaves and a becket.The 2.25 in (57 mm) blocks are compact and lightweight, with fast trim and release under high or low loads. Perfect for dinghies, scows, beachcats and iceboats, as well as small offshore racers and cruisers.SpecificationsSheave diameter: (in) 2 1/4Length: (in) 5 1/2Weight: (oz) 9 1/2Max. line diameter: (in) 7/16Shackle pin diameter: (in) 1/4Max. working load: (lb) 1000Breaking load: (lb) 3000