Barton Marine 04420 Size 4 Fiddle Reverse Shackle Block Barton plain bearing blocks have a precision moulded Acetal sheave running on a large diameter brass bearing, ensuring free running under the highest of loads. Sheave Size: Single: 58mm x 17mm (2-1/4" x 5/8"). Fiddle: 32/58mm x 17mm (1-1/4" / 2-1/4" x 5/8"). Max Rope Diameter: 12mm (7/16"). Break Load: 1260kg (2,770lbs). Length: 175mm(6.89"). SWL: 630kg (1,385lbs). Box Dimensions: 1"H x 3"W x 8"L. Weight: 0.6lbs.