Ronstan Series 55 Ball Bearing Orbit Block™ - Single - Becket - Swivel Head

The Ronstan Series 55 Ball Bearing Orbit Block with single becket and swivel head is a precision-engineered rigging component designed for sailors, riggers, and marine equipment specialists who demand minimal weight without sacrificing load capacity. Built to excel in demanding sailing conditions and high-performance applications, this block represents decades of Ronstan engineering focused on reducing total system weight while maintaining structural integrity. Whether you're optimizing a racing yacht's standing rigging or managing heavy-duty load management, the Series 55 delivers the weight-to-strength ratio that professionals rely on.

The Series 55 Ball Bearing Orbit Block features Ronstan's patented orbital sheave design, which concentrates bearing contact only in active load zones, dramatically reducing friction and extending component life compared to traditional fixed-bearing blocks. The ball bearing construction ensures smooth, efficient load transfer with minimal resistance, while the swivel head design permits natural alignment with load lines and eliminates binding during dynamic rigging scenarios. Weighing just 0.3 pounds and measuring 3 x 1 x 6 inches, this compact block delivers working load efficiency kilogram for kilogram that ranks among the world's lightest in its class, without compromising durability or long-term reliability.

This single becket configuration is ideal for applications requiring a fixed attachment point with a floating sheave, making it suitable for mainsheet systems, traveler controls, and load-tensioning applications across cruising and racing platforms. The swivel head accommodates natural load angles and reduces stress concentrations at the attachment point, extending the service life of both the block and connected rigging hardware. Installation is straightforward with standard shackle or pin connections; ensure proper load rating verification before deployment in critical structural applications.