Rooster has 3 diameters of Carbon Tiller Extensions products, namely a 25mm, 22mm and 19mm diameters. To enable a simple method to change the rubber UJ (or to cut down the tiller), a small carbon insert in used in the lower end of the extension to accommodate the UJ fitting.

This is an insert that fits between the Rooster Carbon Extension and the universal joint. You should be able to retain your existing insert if you replace the universal joint but if you lose it, you will need one of these.

This insert is suitable for the Rooster 19mm diameter extension.

Sleeve Properties for the 19mm Tiller Extension