Designed to reduce the chance of tipping under propulsion or braking.
To install, simply remove the lid of the battery box and remove the batteries.
Inside you will find 4 holes in the battery box. Place a washer on a screw and feed the thread through the hole (the washer and screw head should be inside the box).
Following this align the anti tip roller bracket over the screw and place a locknut on the end, repeat this procedure to fit the roller.
Replace batteries and you are finished.