Barton Marine 45mm Fiddle Swivel Block Size 3Barton Size3 Plain 45mm Block Barton Plain 45mm Blocks have 45mm (1 ) sheave Barton Size3 Plain 45mm Block Key Features : Suitable for use as mainsheet, vangs, lead blocks or wherever a powerful and compact purchase system is required on dinghies, dayboats and lightweight cruisers Suitable for up to 10mm (3 8) rope The size 3 Barton plain bearing blocks have 45mm (1 ) sheave size 3 block range incorporates modern design with stainless steel frames and