Ronstan RF40171 Series 40 Ball Bearing Block Single Upright Lead

The Ronstan Series 40 Ball Bearing Block is a low-profile lead block designed for redirecting halyards and sail controls back to cleats or jammers. This single upright lead configuration features precision-molded Acetal sheaves running on a 2-stage ball bearing system that delivers consistent high performance and minimal friction across the full load range.

Key Features:

• 2-stage Acetal ball bearing system for smooth, low-friction operation
• UV-stabilized Acetal sheave for durability in marine environments
• Grade 316 stainless steel load housing for corrosion resistance
• Low-profile design ideal for deck mounting
• Precision-molded construction ensures reliable performance

Typical Applications:

• Halyard control at mast base
• Sail control line routing
• Rigging systems on sailboats and yachts

The upright lead orientation makes this block particularly well-suited for situations where lines need to be redirected vertically before running horizontally to cleats or jammers. Built to Ronstan's exacting standards, this Series 40 block delivers professional-grade performance for demanding marine applications.