Carbo fiddle blocks have black nylon bodies reinforced with long strand glass for exceptional strength and light weight. They feature high-load ball bearings with rounded races for high contact, low friction operation. • Use 40 mm on 3:1 and 4:1 tackles on dinghy vangs and mainsheets, and controls such as cunninghams and internal boom outhauls on larger boats • Cam arm assemblies can be adjusted in a wide range of positions • Open design makes for easy maintenance • See separate entry for ratchet fiddle blocks