This handy tool allows you to easily remove/install those pesky plugs at either end of your Ninebot ES steering shaft tube.
See the plug removal tool in action in the following tutorials:
Open-source design! Download the FREE .STL files for the Plug Removal Tool on Thingiverse.
Note: The two pegs can be helpful but they aren't necessary. The inset notches provide sufficient grip to remove the plugs and they're a lot more durable. The pegs almost always break after a few uses but I've just left them in the design because they can sometimes be helpful if the plastic plug you're trying to remove was previously damaged and the notches can't grip it well. If you want to protect the pegs, just be careful to insert the removal tool perfectly vertically and seat the pegs evenly before twisting.