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-205 is a low profile configuration for use when installation is at deck level and when smaller blocks are used. This base can be used with 57 mm Carbo® Air® 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 in standard sizing.