Check the listing for details. 57mm Single Swivel Shackle, Becket Block - Master BB-0502F. Condition: Brand New. Listed at 41.84 USD. Product Specifications 57mm Single Swivel Shackle, Becket Block - Master BB-0502F Sheave Ø (mm) 57 mm Sheave Ø (in) 2 1/4 in Maximum line Ø (mm) 10 mm Maximum line Ø (in) 3/8 in MWL / BL (kg) 370 / 1200 kg MWL / BL (lb) 814 / 2640 lb Product range – Ball Bearing Blocks Master ball bearing blocks are available in 22mm, 29mm, 40mm, 57mm and 75mm sizes and multiple configurations. The range features: low friction ball bearings combined with a self-lubricating Acetel bushing for speed and minimal friction, high strength side plates made from a UV stabilised, stiff glass-fibre reinforced Nylon composite for lightness,locking mechanism so that the shackle in the “single swivel shackle” models can either rotate freely or be locked in position (only from 57mm). becket pin which is easy to remove or lock into the keyhole with no tools, adjustable cam cleat arms for an optimal exit angle of sheets (only from 40mm).