According to the manufacturer, the climbing height is 2 cm.
Depending on the angle of approach, it has already climbed 2.5 cm in my case, but then didn't come back and had to be freed manually.

I have a 4cm edge and the Robo doesn't manage to drive up it despite the 3D printed ramp. But 3cm could work with a ramp, because the main problem for me is that it recognises the threshold as a wall despite the ramp, probably because of the height.