Harken 125mm Block

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Calculated at Checkout

The entire line of Black Magic® AirBlocks® has been redesigned with a sleek new look. Their unique, performance-packed engineering remains exactly the same. These strong, lightweight blocks feature free-rolling high-load Torlon® roller bearings for a high strength-to weight ratio. 

Like all AirBlocks®, the three-way head swivels/locks in front/side positions. Blocks are easily disassembled with a single hex wrench. 

Part Number: HK3256


Sheave Ø (mm) 125 mm
Sheave Ø (in) 4 15/16 in
Length (mm) 254 mm
Length (in) 10 in
Weight (g) 1058 g
Weight (oz) 37.31 oz
Shackle pin Ø (mm) 12 mm
Shackle pin Ø (in) 1/2 in
Maximum line Ø (mm) 19 mm
Maximum line Ø (in) 3/4 in
Maximum working load (kg) 4990 kg
Maximum working load (lb) 11000 lb
Breaking load (kg) 9977 kg
Breaking load (lb) 22000 lb


Need help to design your Harken system - take a look here for the Harken System Guides and Drawings

Or perhaps you need some other information (load calculators, block selectors, service instructions or manuals)?   Take a look here for all the official Harken Support Information