The Joint Universal rudder stick, rubber, connects a tiller extension with a tiller. The flexible rubber allows for a full range of motion with the tiller extension. New tiller extensions come with a joint universal, so you can use this one to replace one that has broken. Includes plastic base for mounting on your tiller and is designed to fit in tiller extension tubes with a .5"/13mm inner diameter, the most common size of small sailboat tiller extensions.