Product Description Harken 125mm Aluminum Loop BlockBlack Magic Air blocks are a top favorite of Big Boat performance racers and cruisers. These lightweight, free-running, powerful performers are used for sail controls that see lots of action: mainsheet, runner, halyard, and spinnaker systems. A center cage keeps Torlon roller bearings separated and parallel to reduce friction. The sheave center carries primary load, allowing a smaller, lighter weight block. The soft-attachment Loop block has a removable deadend post for attachment to a padeye. Lashings can also be used. Torlon is a registered trademark of Solvay Advanced Polymers L.L.C. Specifications: Sheave Ø (mm) 125 mm Sheave Ø (in) 4 15/16 in Length (mm) 163 mm Length (in) 6 in Width (mm) 127 mm Width (in) 5 in Weight (g) 674 g Weight (oz) 23.78 oz Maximum line Ø (mm) 19 mm Maximum line Ø (in) 3/4 in Maximum working load (kg) 4990 kg Maximum working load (lb) 11000 lb Breaking load (kg) 9979 kg Breaking load (lb) 22000 lb