Harken 3218 57mm Double Black Magic High-Load Swivel Block With Becket

HARKEN 3218 Double Black Magic® AirBlock® with Becket - 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. Used on offshore boats, these strong, lightweight blocks feature high-load Torlon® roller bearings for a high strength-to-weight ratio and reduced wear. Rollers are housed in a center cage and stay parallel for low-friction efficiency. Sculpted hardcoat-anodized aluminum side plates protect sideload ball bearings. Dissimilar metals are isolated to minimize corrosion. Like all Black Magic® AirBlocks®, the three-way head swivels/locks in front/side positions. Blocks are easily disassembled with a single hex wrench. Standard blocks have 17-4 PH stainless head posts. Low-load blocks use Torlon® rollers and 316 stainless steel shackles. Use for: Sheets Halyards Running backstays Control lines Specifications: Sheave Diameter - 57mm (2-1/4") Max Line Diameter - 7/16" (12mm) Mfg No. Description Length Shackle PinDiameter Max WorkingLoad BreakingLoad Weight 3218 Double / swivel w/ becket 6"(152mm) 5/16"(8mm) 3600 Lbs(1633kg) 7200 Lbs(3261kg) 12.43 oz.(352g)