Atmotube 1.0 (Indiegogo edition) has a VOC sensor that works in 1 second mode, which means the device takes air readings every second and sends them to your smartphone.
Atmotube 2.0 version takes VOC readings every 10 seconds and has significantly longer battery life. Requires periodic manual calibration.
Atmotube PLUS is an enhanced version of the Atmotube 2.0, which features VOC sensors with self-calibration, longer battery life, increased antenna performance, built-in weather station and improved portability.
Atmotube PRO version has all features of Atmotube PLUS and PM1/PM2.5/PM10 sensor