Normally, I avoid quartz watches, since they are technically competely uninteresting and boring. This NOVUS from the seventies is the well-known exception here.
In contrast to normal quartz watches with LCD- or analogue displays, this watch tells their time with four red-lighting LEDs. Since LEDs are terribly power consuming, the time is only shown, when you press the key. And because of the power consumption, this watch is powered by a pair of the largest 1.5V cells available, LR44 (5.6mm height, 13mm diameter). Nevertheless, they only last a year.
This watch has got a stainless steel case with integrated stainless steel band, screwed down stainless steel back and a red mineral glass.
By pressing the button, you first see the time in hours and minutes. If you keep the key pressed, you can see the seconds flashing. If you press the key twice, you can see the weekday and date; if you keep the key pressed, you can see the month and day.
The watch module WM-09 was made by National Semiconductors and consists of a plastic case, a printed circuit board with chip on it (with very fragile and tiny wired), an almost atypically small quartz crystal and a four-digit seven segment LED display under magnifying glasses. It was the last and latest module produced by Ntional Panasonic.
I refused opening the module, since I know, that I'd instantly damage the tiny wires of the chip.
Since LED watches were expensive to made, and were unhandy for the consumers, they were produced only about five years from 1972 on. Five years later, they are almost competely replaced by LCD based watches, who offered constant displaying of the time and a much longer battery life. Today, there are a few LED watches produced again (e.g. by Fossil), but of course, they are not the original ones and so not collectible.
Those few original exemplars, who survived and were not destroyed by leaking batteries are sought after. And if a seller knows, what he's selling, he sells them for a lot of money, often even in bad condition.
So, lucky me, who managed to get that gem for only four dollars. Without batteries.
Many thanks to Jürgen Hofstädter for further infos of this watch.