Size 3 Single Plain Bearing Block with SwivelBarton plain bearing blocks have a precision molded acetal sheave running on a large diameter brass bearing, ensuring free running under the highest of loads.Features: Fully swiveling head with removable shackle For use on dinghies, day boats, and light cruising yachts Specifications & Dimensions: Length: (mm) 100 / (inch) 3-15/16" Weight (grams): 73 g. Single (mm) 45 x 13 / (inch) 1-3/4" x 1/2" Max Rope Diameter: (mm) 10 / (inch) 3/8" SWL: (kg) 400 / (lbs.) 881 Break Load: (kg) 800 / (lbs.) 1763 Note: break loads where break and safe working loads are stated, it is assumed that all sheaves are evenly loaded as in a purchase tackle