Counterweight for the Landroid robotic lawnmower (9v battery style)

The WORX Landroid robotic lawnmower is slightly front-heavy, which can lead to wheel slippage on slippery grass or uphill due to poor traction. To solve this problem, a 3D-printable weight tank has been designed that is mounted on the back of the robot. The tank has a screw cap through which weight, such as sand, can be added to improve traction.

I printed this with PETG and the caps and texts with PLA.