57mm Black Magic® Low-Load Single Block

Harken 57mm Black Magic® low-load single block with shackle that locks in two directions or swivels to keep line from twisting. 

The entire line of Black Magic® AirBlocks® offer a sleek and polished look. Their unique performance engineering remains the staple of the Black Magic line of blocks. These strong, lightweight blocks feature free-rolling, high-load Torlon® roller bearings for a high strength-to-weight ratio. Used for dynamic high load sail controls including mainsheets, runners, halyards and spinnaker systems.

Air blocks are easy to clean and service. They have few parts and no loose balls or rollers to misplace. Unlike blocks that are riveted, fasteners allow quick disassembly with a single hex wrench.

Key Features

• Lightweight blocks with high-load Torlon® roller bearings for a high strength-to-weight ratio
• Ideal for sail controls including mainsheet, runner, halyard, and spinnaker systems
• Center cage keeps Torlon® roller bearings separated and parallel to reduce friction
• Sheaves have radiused edges to protect today’s high-tech line
• Stainless steel swivel shackle
• Low-load blocks have red isolators
• Sheave Diameter: 2 1/4" (57 mm)
• Max. Line Diameter: 7/16" (12 mm)
• Max. Working Load (MWL): 1655 lb. (750 kg) 
• Breaking Load: 3310 lb. (1500 kg)  
• Weight: 5.44 oz. (154 g)
• Length: 4 11/16" (119 mm)