Ronstan Series 20 Ball Bearing Block - Single, Loop Mount

The Ronstan Series 20 Ball Bearing Block – Single, Loop Mount is a precision-engineered pulley system designed for sailing, rigging, and general mechanical applications where smooth load transfer and minimal friction are critical. This lightweight, single-point attachment block serves as the backbone of modern rope and cable management systems, enabling sailors and rigging professionals to redirect loads efficiently while maintaining system integrity under demanding conditions.

Built with precision-molded acetal sheaves rotating on stainless steel or torlon ball bearings, the Series 20 block delivers exceptionally low friction and high dynamic load capacity despite its compact 2 x 1 x 4-inch footprint and featherweight 0.1-pound construction. The stainless steel bearing surfaces resist corrosion in saltwater environments, while the ball-bearing design ensures smooth operation even under sustained load, reducing wear on rigging lines and extending service life. The loop mount configuration provides a secure, single-point connection suitable for boom gallows, mainsheet systems, and auxiliary rigging installations.

Sailors, marine technicians, and rigging crews rely on the Ronstan Series 20 for applications ranging from cruising yachts to high-performance racing vessels, as well as industrial lifting and material-handling setups. Its compact profile and exceptional static and dynamic load ratings make it ideal for retrofit installations where space is limited or weight savings are essential. The loop mount accepts standard shackles or carabiners, ensuring compatibility with existing rigging systems and offering flexibility in deployment across multiple vessel types and configurations.