Harken 40mm Zircon Blocks

Harken Zircon blocks feature industrial ceramic ball bearings, the ultimate in low friction efficiency, absorbing far less energy before they roll - ceramic is the household name for the metal element Zirconium.

Harken designed the block with the Zircon bearings mounted inside caged races – the cages keep the bearings separated, preventing them from bunching, touching and stopping each other. 

Zircon ball bearings are the ultimate in hardness and smoothness, approximately seven and a half times stronger in compression than stainless bearings.

Harken Zircon bearing blocks are supremely responsive to the merest hint of sheet load fluctuation, delivering improved sail shape and more speed for a good crew, especially in light airs.

Harken 40mm Zircon Blocks: Facts, Features and Plus Factors

• Sheave Diameter: 40mm
• Optimum Line Diameter: 6mm
• Multiple configuration options
• Harken's highest efficiency, lowest friction block
• Zirconium/Ceramic Ball Bearings: Seven and a half times stronger in compression than stainless steel
• Bearings mounted in ages to minimise rolling resistance 
• UV-stabilised fibre-reinforced composite construction
• Structural head for soft attachment, Dyneema line not included

MBL = Harken Manufacturer Break Load

MWL = Harken Maximum Working Load

Ø = diameter