Product review (5 stars): Easy to carry and works great
The unit is small and light.  The display is clear and the backlight makes it easy to read  I carry it in my tool bag and it is so small I forget I have it.  I use it to check weather stations at work.  I finally had a chance to check this against a real weather station, a Campbell Scientific station that shows up on the NOAA website.  I had 45 degrees F and 47% RH and the weather station had 44  degrees F and 43% RH. I was about 200 yards from the weather station, so this is as close as expected.  The wind was harder to check.  The WM-3 readings were changing a lot, depending on which way I faced it.  The anemometer I was next to was reading 4 to 5 mph.  The WM-3 was reading 4 to 9 with the average function showing 5.3 mph.  The WM-3 responds quicker to the speed changes unless you use the average function.  the averaging starts when you turn the power on so you have to hold it in the wind as you turn it on to get the average. I also used it to check conditions indoors, and found it takes a few minutes for the temperature and humidity to stabilize.  It showed the rise in humidity a few minutes after I turned on a humidifier in the room. Overall it works great.