The Barton Marine 45mm sheave Series 3 pulley blocks incorporate modern design, with stainless steel frames and the latest advanced materials, using 30% fibre glass filled nylon acetal sheaves to maximise their strength whilst keeping weight to the minimum. The Barton Series 3 range is suitable for use as mainsheet, vangs and lead blocks or wherever a powerfull and compact tackle is required for dinghies to dayboats and lightweight cruisers. A comprehensive range of multiple sheave options, together with fiddles and cam cleat blocks, allow powerful, lightweight tackles to be achieved. Available as Plain or Ball Bearing Blocks. Plain bearing blocks: Barton plain bearing blocks have a precision moulded acetal sheave running on a large diameter brass bearing, ensuring free running under the highest of loads. Ball bearing blocks: With our unique super-low friction ball race systems, featuring acetal sheaves and delrin ball bearings, running on a large diameter centre boss. This allows us to fit more load-bearing balls, which ensure extremely low friction performance, even under high loads.