Because I am making my own PCB:s I needed an exposure timer for the UV lamps.
The lams are of the fluorescent type and they must be ignited before they can emit light. Normally one has a device called "igniter" which is actually a vacuum tube delay having bimetallic contacts in it. The operation of the lamps is not very reliable with that one.
There is a rotary switch which is used to select the time. Also there is a button to start the thing. The button has a flashing light on it.