Harken swivel bases are ideal when leads must rotate to face the trimmer. Ball bearing swivel bases feature dual rows of Delrin® ball bearings that swivel freely even under high loads. Bases include stand-up springs and a U-Adaptor to accept a variety of appropriate blocks. The H-144 is the standard configuration with a tall arm. It is ideal for mounting in the cockpit or for use on larger keelboats and small offshore boats. This base can be used with 57 mm & 75 mm Carbo® Air® Blocks, including Ratchet and Ratchamatic® Blocks. A 365 Standard Carbo Cam Cleat is included. Installation requires hole spacing of 19mm and 5RH fasteners (not supplied). This cleat is also available a low profile version.