Great Devices!
I have these Wireless Tags on all the doors of my house, so not only do I know when they are opening/closing, but also I know the temperature and humidity at each location! I can also use the tag's temperature to control my Nest thermostat so that it will come on/off based on a Tag's temperature and not the temperature at the thermostat (full disclosure, I haven't testing that feature but it is set up to work).