The clock shows the seconds, minutes and hours by industry mA meters.
It is drive by a DIY kit from a German company called ELV.
The CPU - Board inside controls a real time clock and get the time from a LW - time - transmitter near Frankfurt.
A switch switches the electronics off, a backup battery keeps the time in the real time clock.
Assembling the KIT is easy because the SMD parts are already soldered on the board.
All parts needed comes with the kit. Even additional trimmer to adjust nearly every type of mA Meter without shunt inside.