This kind of Electrolux knobs have the marking at the top, making it hard to see what temperature one has set on the oven.

This little print adds an arrow to the knob. It has some friction, so it should not move when the knob is turned.

Knob outer diameter: 41 mm

I first tried doing a variant that is mostly inside the knob, with just the arrow sticking out, but it turns out that the screws right under the knob are very close to the inner wall of the knob. Hence, the outside solution.