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Harken 57mm Aluminum Low Load Black Magic Block w/Swivel

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57mm Aluminum Low Load Black Magic Block with Swivel

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. Shackle blocks lock in two directions or swivel to keep the line from twisting. Low-load blocks have red isolators. They use Torlon® rollers and 316 stainless steel shackles. Standard blocks have 17-4 PH stainless head posts. Torlon is a registered trademark of Solvay Advanced Polymers L.L.C. 


  • Sheave: 57mm/2-1/4in
  • Length: 119mm/4-11/16in
  • Weight: 154g/5.44oz
  • Shackle Pin: 6mm/1/4in
  • Maximum Line: 12mm / 7/16in
  • Maximum Working Load: 7/16kg / 1655lbs
  • Breaking Load: 1500kg / 3300lb