Wow! I am amazed those are still available after so long!
That was my first anemometer back in the late '70's. very simple and quite effective, although I later found it under-read a bit when compared with high end anemometer (as most low cost others I have tested also do). I tuned it up with a hot needle in the bleeder hole.
Since the early 90's I have had an analogue vane anemometer. German made. Instrument quality. Was actually quite expensive back then and I find, surprisingly, it too is still available:
www.svb24.com/en/handheld-anemometer.html 
I have tried and compared numerous other Anemometers over the years, and I still recon this is the best one for a number of reasons.
No battery required. No circuts to corrode or drown. In my view, it gives a better overall visual indication of the wind range than a digital number readout. Multiple scales simply by turning it around (Knots, M/s, Beaufort scale, Km/h). It is virtually non directional - many others read low if they are not lined up precisely with the wind direction (up or down
and side to side). It large enough not to lose and small enough to keep handy. It has a nice protective clear guard cap.
The icing on the cake: It is extremely accurate! (tested against many other instrument quality anemometers).
But, it is important to note that, IMHO, accuracy is not the be all and end all most of the time. It's more important to know how to use the info to make a better choice of sail, board and fin sizes. Stick with something that works consistently and get used to it.
