![Ronstan Series 40 Ball Bearing Block - Single Upright Lead [RF40171]](https://cdn11.bigcommerce.com/s-6g54mu6qkm/images/stencil/600x600/products/20964/21664/70615XL__91556.1530002945.jpg?c=2 "Ronstan Series 40 Ball Bearing Block - Single Upright Lead [RF40171]")
![Ronstan Series 40 Ball Bearing Block - Single Upright Lead [RF40171]](https://cdn11.bigcommerce.com/s-6g54mu6qkm/images/stencil/1280x1280/products/20964/21664/70615XL__91556.1530002945.jpg?c=2 "Ronstan Series 40 Ball Bearing Block - Single Upright Lead [RF40171]")
Product Overview
Series 40 Ball Bearing Block - Single Upright Lead
Lead blocks are a low profile solution for leading halyards or other rig sail controls back to cleats or jammers. Precision molded Acetal sheaves running on Acetal or Torlon® ball bearings provide high performance & low friction. The 2-stage ball bearing system provides consistent performance over the full load range.
Applications:
- Typically used for halyards at the mast base.
Materials:
- Acetal ball bearings
- UV stabilized Acetal sheave
- Grade 316 stainless steel load housing
![Ronstan Series 20 Ball Bearing Block - Upright Lead [RF20171]](https://cdn11.bigcommerce.com/s-6g54mu6qkm/images/stencil/500x659/products/11158/11870/55137XL__14804.1529968304.jpg?c=2 "Ronstan Series 20 Ball Bearing Block - Upright Lead [RF20171]")
![Ronstan Series 15 Ball Bearing Utility Block - Upright Lead Block [RF15171]](https://cdn11.bigcommerce.com/s-6g54mu6qkm/images/stencil/500x659/products/21303/22002/71024XL__79006.1530003568.jpg?c=2 "Ronstan Series 15 Ball Bearing Utility Block - Upright Lead Block [RF15171]")
![Ronstan Series 40 All Purpose Block - Single Upright Lead [RF41171]](https://cdn11.bigcommerce.com/s-6g54mu6qkm/images/stencil/500x659/products/50735/67417/70602XL__82729.1678916553.jpg?c=2 "Ronstan Series 40 All Purpose Block - Single Upright Lead [RF41171]")
![Ronstan Series 55 BB Ball Bearing Orbit Block - Upright Lead [RF55171]](https://cdn11.bigcommerce.com/s-6g54mu6qkm/images/stencil/500x659/products/39958/52025/88830XL__09191.1617155425.jpg?c=2 "Ronstan Series 55 BB Ball Bearing Orbit Block - Upright Lead [RF55171]")
![Ronstan Series 40 Ball Bearing Block - Single - Becket [RF40110]](https://cdn11.bigcommerce.com/s-6g54mu6qkm/images/stencil/500x659/products/45210/60193/70613XL__13634.1651532301.jpg?c=2 "Ronstan Series 40 Ball Bearing Block - Single - Becket [RF40110]")
![Ronstan Series 40 Ball Bearing Block - Single - Stand Up [RF40140]](https://cdn11.bigcommerce.com/s-6g54mu6qkm/images/stencil/500x659/products/11226/11938/55211XL__21934.1529968426.jpg?c=2 "Ronstan Series 40 Ball Bearing Block - Single - Stand Up [RF40140]")
![Ronstan Series 40 Ball Bearing Block - Single - Universal Head [RF40100]](https://cdn11.bigcommerce.com/s-6g54mu6qkm/images/stencil/500x659/products/11225/11937/55210XL__66052.1529968425.jpg?c=2 "Ronstan Series 40 Ball Bearing Block - Single - Universal Head [RF40100]")
![Ronstan Series 40 Ball Bearing Block - Single - Loop Top [RF40101]](https://cdn11.bigcommerce.com/s-6g54mu6qkm/images/stencil/500x659/products/20960/21660/70611XL__29193.1530002938.jpg?c=2 "Ronstan Series 40 Ball Bearing Block - Single - Loop Top [RF40101]")
![Ronstan Series 50 All Purpose Block - Single Upright Lead [RF51171]](https://cdn11.bigcommerce.com/s-6g54mu6qkm/images/stencil/500x659/products/21014/21714/70682XL__47099.1530003033.jpg?c=2 "Ronstan Series 50 All Purpose Block - Single Upright Lead [RF51171]")