This XIKAR PuroTemp Wireless Hygrometer Remote Sensor unit can be added on to the Puro Temp Wireless base unit and placed inside your humidor when you need to remotely read the humidity inside more than 1 humidor/location (up to 3 humidors/locations within 60 feet range). Accuracy has been tested to +-2% humidity and 1 degree Celsius. The XIKAR PuroTemp Wireless Hygrometer base unit is sold separately as the XIKAR PuroTemp Wireless Hygrometer System. Size: 3”1/4L x 2”1/2W x ¾”H