This swivel base was the standard on new Flying Scots for quite some time. The current new Flying Scots now use the Ronstan swivel base as standard equipment (linked below). The holes on the Ronstan and Harken swivel bases do not line up so if this is a concern for you and you currently have a Harken swivel base we would suggest continuing to use this base.
Harken ball bearing swivel bases feature dual rows of Delrin® ball bearings that swivel freely even underhigh loads. Bases include stand-up springs and a U-adaptor to accept a variety of appropriate blocks. The 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 that use 3.00 in (76 mm) plastic blocks.
Delrin® is a registered trademark of E. I. du Pont de Nemours and Company or its affiliates.