Harkens beskrivning (på engelska) Black 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.