If you have bought a RHD Earlybay Throttle Kit and it never came with these fitted then I think these are a must have item to add to your kit.
These fit on the long rod under your cab floor. (2 x Boots supplied in the kit )
They help keep all the dirt and water away from the 2 main swivel joints on the kit, so you can lubricate the joint then cover up. The rubbers are a good tight fit.