Attached are the wires for my old Thermostat (Honeywell CT3500) and Control Board. As you can see the C-Wire is on the Control Board but not on the Thermostat. This means that a C-Wire Adapter (Provided in the box) needs to be installed next to the Control Board. (Realized later that there might be a C-Wire floating in the hole behind the Thermostat. My Thermostat uses batteries, so C-Wire is not required. There is no harm in pulling the wires out from the hole after removing them from the old Thermostat and checking if there is a C-Wire. It is much easier to install if the C-Wire is presented)Now comes to the fun parts for installing the C-Wire Adapter. There are two Y-Wires and one C-Wire on the Control Board. The instructions from the WYZE App did not have this configuration. Called tech support. After several checks, I got the answer to leave the C-Wire open and merge two Y-Wires. It is simple and easy by following the WYZE App instructions and finishing the installation. Turned on the power and again it was straightforward to add the Thermostat to WYZE App. During the testing, heating passed but cooling failed. Called tech support again and some time troubleshooting without success (Tech supports were overall very good, no long waiting time, follow up closely, easy to communicate with both phone and email for pictures etc. The issue was resolved on the same day before tech’s further follow up). Did some research and tried to put back the original C-Wire to the Control Board (with the C-Wire from the C-Wire Adapter on the same terminal). It worked surprisingly. Later it was realized that the diagram from the WYZE App did indicate that the original C-Wire should be kept with C-Wire from the C-Wire Adapter (See attached picture). But there is no word.PRO: The Thermostat looks nice (see attached for installed) and well made. Though there were some bumps for me due to non-standard configuration, the installation and setup are overall clear and straightforward.CON: WYZE Thermostat did not qualify for local utility discount or rebate.Some helpful tips: 1. Do not forget to remove the plastic cover sheet, otherwise the motion sensor to activate the display won’t work (Still works if you touch or turn the display wheel with the sheet on). 2. The Thermostat was first tested without fastening to the wall (So it wouldn’t damage the wall in case it was not working). Got the problem to remove the face panel. Finally, a small flat head screwdriver was used to pry it out through the gap. If I knew this issue early, I would have used a small Bolt/Nut to fasten the base plate to the optional wall plate (Provided in the box). So, it will be easy to just pull the face panel out by holding the wall plate. This problem will not exist if you follow the instructions and fasten the base plate to the wall before putting the face panel. 3. Make sure the setting value in the Temperature Preferences and Schedule is indeed what you wanted to prevent surprising action of the HVAC system. 4. There is no harm to calibrate the temperature and add temperature correction in Advanced settings. Mine was 2~3 degrees off. The temperature correction is a better place to adjust the temperature setting temporarily while keeping it at Auto. Here is an example: turn on the AC 1degree cooler – it is much easier just to add 1 degree in the temperature correction. Decrease 1 degree (Got 1 degree hotter) if you want to save energy. After using it for about a week, the Thermostat ran well as expected and the App is easy to use.Update rating to 5-star from 4-star after running for more than three weeks: Never has issue and is easy to control.Update after 9 months: never had a problem; found out that the climate sensor (default is the room sensor) can also be used to control the room temperature with rules; in case there is wifi-off issue, do not reset from the device, instead reset by power off and on through the power panel.