This is a HS71512 Pro Series3 Radon Gas Detector made by SafetySiren. It continuously monitors radon levels and maintains a short-term and long-term average. I've used this for quite a few years and the readings have been stable and believable. My levels were around 15 pc/l before a mitigation system was installed and fell to below 4 pc/l once the system was running. required when Bluetooth is in use. Tap "Allow" when prompted with messages such as "Allow RADON EYE to access photos, media, and files on your device?" and "Allow RADON EYE to access this device's location?" 5. Turn Bluetooth on to pair your phone with RADON EYE. After pairing, your RADON EYE stays paired until you unpair RADON EYE. 6. fileslib.