Harken 57mm Double Block-Swivel

57 mm Carbo These smooth-running powerful performers make trimming easy, no matter how hard the wind blows. Carbo Air blocks are made of tough reinforced composite in a size and style to fit any system: singles, doubles, triples, quads, and quints; ratchets and fiddles; soft and hard attach. Perfect for main, jib and spinnaker sheets on dinghies and sportboats; control lines on boats of all sizes.Lightweight, strong and reliable fiber-reinforced composite construction.Ball bearings, sheave, and sideplates are UV-stabilized.     Sheave Ø (mm) 57 mm Sheave Ø (in) 2 1/4 in Maximum line Ø (mm) 10 mm Maximum line Ø (in) 3/8 in Maximum working load (kg) 720 kg Maximum working load (lb) 1584 lb