Harken 57mm Carbo Air Fiddle Block w/Swivel & Becket - Fishing. This piece of Fishing Equipment from the experts at Harken is a low-friction Carbo Air block that is guaranteed to be messge with little to no friction keeping you on the water longer. For an amazing way to give your fishing trips the edge choose the Harken Carbo Air 57mm Fiddle Block w/Swivel & Becket. Specifications for Harken 57mm Carbo Air Fiddle Block w/Swivel & Becket: Manufacturer: Harken Color: Black Quantity: 1 Package Contents: Harken 57mm Carbo Air Fiddle Block w/Swivel & Becket Harken 2622F: 57mm Carbo Air Fiddle Block w/Swivel & Becket - Fishing