Harken 3221 57mm Single Black Magic High-Load Air Block Lockoff Footblock

HARKEN Black Magic® Aluminum Lockoff Footblock - 57mm  NEW! The entire line of Black Magic® AirBlocks® has been redesigned with a sleek new look. Their unique, performance-packed engineering remains exactly the same. Carrying some of the highest loads imposed by running rigging, this strong, lightweight block features Torlon® roller bearings housed in a center cage. Rollers stay parallel for low-friction efficiency. Sculpted hardcoat-anodized aluminum side plates protect sideload ball bearings. Dissimilar metals are isolated to minimize corrosion. This block is easily disassembled with a single hex wrench.Either metric or imperial flathead fasteners may be used for mounting and are not exposed.Use for: Genoas Spinnakers Specifications: Sheave Diameter - 57mm (2-1/4") Max Line Diameter - 7/16" (12mm) Fasteners - 4 x 1/4" (6mm) FH Mfg No. Description Length Height Max WorkingLoad BreakingLoad Weight 3221 Single lockout / high-load 3-5/16"(84mm) 1"(25mm) 2500 Lbs(1134kg) 5000 Lb