Size 3 Single Plain Bearing Block with Swivel. Barton 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. Additional product details from marketplace: fully swiveling head with removable shackle; product dimensions approx 1.77" L x 1.77" W; package dimensions 6 x 2 x 2 inches; package weight 3.2 ounces.