The Carbo Air blocks are known for their lightweight, strength, reliability and affordability. They pair well with the popular Harken Black Magic line and have high working loads, making them ideal for safe and effortless trimming. The 40 mm fiddle block is an excellent option for a variety of tasks on smaller and larger boats, including 3:1 and 4:1 tackles for dinghy vangs and mainsheets, as well as for controls like cunninghams and internal boom outhauls.