The Sure Test® GroGuru Base (Collector) is used to collect data from the various Stems (sold separately) with sensors. The Base then forwards this information to the cloud. A single Base can be used to communicate with up to 1,000 Stems depending on deployment. This is powered by an indoor rated 110 volt power supply. Simply plug it in and it is ready to go. Download the App: iOS/Android phone/tablet Apps make it possible for you to see trends and set thresholds to generate automated alerts.