Harken black Magic Air Block 57 mm Aluminum Double Block with Swivel HK3217

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 line from twisting.

Sheave Ø (mm)57 mm
Maximum line Ø (mm)12 mm
Maximum working load (kg)1633 kg