The Easydrive top is designed like a torsion axle on a farm wagon. The inner hub is independant of the outer shell. The space between the inner hub and the outer shell is filled with shock absorbing materials. It also has a vertical cushion designed into it. The shock absorbing feature adds life to the drive motor components. The easydrive top fits all the Mr. Manhole cutters.
Product Link: https://mrmanhole.com/product/easy-drive-top-2-1-2-kit-platinum-series/