Great for dinghy mainsheets on boats such as the Laser, 470 and 49er. Spinnaker sheets on dinghies, especially modern asymmetric classes, sportboat mainsheet systems, vang, traveller and control lines on larger boats. Pivoting lead blocks are great for sportboats and small keelboat spinnaker sheets and other control line applications on larger boats. The ratchet on/off switch appears on both sides of the block and the switch can be operated under load. One of the switches can be removed if desired. Sheave: Alloy Ball Bearings: Carbon Black Acetal, Torlon ratchet pawl Sheave Size: 2-3/8" (60mm) Line Dia.: 3/8" (10mm) Cheek Material/Finish: Alloy Shackle/Strap Type: Grade 316 stainless-steel forged shackle