The black Gearbox of the Roomba was the second set of brushes and certainly the best to be produced for the Roomba series ranging from 520 to 580. It can also be included in the 600 series.

The interesting feature is that the whole mechanism runs on bushings and ball bearings. In this way, the motor makes less effort and the brushes turn faster and with less friction, which translates into a battery saving and a more attenuated noise.

The gearbox opens by leveraging the two front fins. The brush is pulled out with the bristles and the brush with the rubber.

Remember to clean the yellow side rollers that are where you roll your hair.

The iRobot also provided a red round cleaning accessory that I found impractical.