This stop-watch timer sports 6 Hitachi CD61 nixie tubes.
It dates from around 1970.
Judging by the brand (“Luctor” from Baarn used to be a
brand of school supplies)
it must have been intended for school use, e.g. timing of experiments
of some kind in a physics class.
There are two buttons at the front: one to reset the counter and a
start/stop button. The connections to both buttons are avalailable on
a 3-pin DIN connector at the back, probably intended to connect the
timer to external switches connected to the experiment to be timed.
Inside view. You can see the circuit board and the 6 nixies, with
the hitachi logo and type number clearly visible.
The technology is TTL, using a basic design.
Inside are 6 SN7490 decimal counters and SN74141 decoder/nixie driver IC's.
On the circuit board there is space for another 2 decimal counters,
so it is possible to change this device into a nixie clock.
There would be one disadvantage to this: because of the TTL technology
used, the power consumption is relatively high (about 15 W).
And I am not sure the power transformer is designed for continuous
What is worse, is that the power supply is not stabilised.
The designer must have been a truly optimistic person.