This wireless interface makes it extremely easy to set up thermostats to the Honeywell HZ432 Redlink zone controller. After connecting the C and R wires to the thermostats for power, the stats linked to the controller individually in seconds. You must link each thermostat, one at a time.It is especially useful if you are changing your HVAC system from single stage equipment to multi stage, as I did. There is no need for any additional wires for the thermostats. You do need the appropriate type stat for the system and it must be Redlink compatible. I selected the Honeywell TH8320R1001 thermostats and they work perfectly. Add the Honeywell Internet Gateway and get the free app for your smart phone and you can view and control all the thermostats in your house from anywhere. A simple solution to what could be a complicated wiring job. Honeywell did a great job with their Redlink devices.Aug.25,2018I would like to add some additional information to my old review. I was recently asked to help an old friend troubleshoot one of his installations. His customer called him because the system would overshoot the temperature and even if he turned the thermostats to system off, the ac would continue to run for a few hours. He spent a few hours checking wiring, programming (it is a 3 zone heat pump installation) and erasing settings and resetting. Nothing he did fixed the problem.I came in and looked everything over. After about 10 minutes of head scratching, it dawned on me. The thermostats are connected to the 432 zone control via Redlink wireless. As I wrote in my original review, I believe Honeywell Redlink is outstanding and have installed it for years. What occurred to me was the THM4000 was mounted on sheet metal ductwork. The installation manual states that you can install it this way. Honeywell, you goofed! The sheet metal acts as a partial shield and intermittently reduces the Redlink signal from the thermostats. The stat will turn the system on but sometimes the THM4000 can't get the command to turn off. I advised my friend to relocate the adapter to a wooden 2x4 and now the system works flawlessly.The reason I never had any issues with Redlink is I never mounted any equipment to duct work or cabinets. I would always mount a small piece of plywood for all the equipment.I just thought I would pass this bit of information on and possibly prevent a potential expensive nightmare for someone.