Hey @Max, welcome to the forums! 
The limit manipulator appears when looking from above, and you can manipulate them asymmetrically by holding the Ctrl key as you drag on one of the corners.
See here and here for more details:
Hey @Max, welcome to the forums!
The limit manipulator appears when looking from above, and you can manipulate them asymmetrically by holding the Ctrl key as you drag on one of the corners.
See here and here for more details: