Harken Carbo Air Triple Swivel Block w/Becket 40mm. This 40mm Carbo Air Triple Swivel Block w/Becket by Harken is a small compact low friction block with a wide range of applications. The Harken Carbo Air Light Weight Trim Swivel Block features a durable stainless body a Delrin sheave and a stainless steel becket. They are perfectly suited for dinghies car and sailboats kite sails spin radial sails and any other application requiring a light weight strong trimmer swivel. For more of the best products for your boat check out our extensive collection of Harken gear. Specifications for Harken 40mm Carbo Air Triple Swivel Block w/Becket: Manufacturer: Harken Color: Black Package Contents: Harken 40mm Carbo Air Triple Swivel Block w/Becket Harken 2641: Carbo Air Triple Swivel Block w/Becket 40mm