These wheels go on top of the squeegee bar on the Mopit 4, 4.5, 5, mini, Mid (Gen 1 and 2), MAX. These wheels help the squeegee bar deflect against the wall to help avoid damage.

It comes with two wheels with built in bearings, two 1/4-20 x .75" bolts (SIP-00001153), and two lock washers (SIP-00001113).