Harken 125 mm Aluminum Air® Runner Black Magic® Block

Runners are used on running backstays of offshore boats to adjust mast bend for different wind conditions.

Integrated sideplate bails and recessed cotter key help produce a smooth design that won’t snag lifelines.

Sideplates and sheaves Hard Lube-anodized for maximum UV protection and a smooth surface. Center cage keeps Torlon® roller bearings separated and parallel to reduce friction.

Torlon is a registered trademark of Solvay Advanced Polymers L.L.C.


  • Breaking load (kg) 9980
  • Clevis pin Ø (mm) 19
  • Length (mm) 195
  • Maximum line Ø (mm) 19
  • Maximum working load (kg) 4990
  • Sheave Ø (mm) 125
  • Weight (g) 844

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