This is a used one-time in-the-box Plug-n-Play Humidity Controller model IHC-200, able to control humidity from 5 to 99.99% RH. It's an easy-to-read humidity controller with accuracy +/-3% RH; It will switch modes between humidification and dehumidification automatically. We used it in controlling room humidity with a steam humidifier, and it worked great. It can be used to control humidity in a grow tent or greenhouse. Alarms when sensor error or humidity reaches preset high or low levels.