The Machine Sentry® app is free from the Google Play store for up to 25 sensors on one geographical site. This is intended for evaluation purposes only as the data is only stored on the handheld device. If more than 25 sensors are to be used on one geographical site, MSF-01 sensor and Machine Sentry® software licences apply for a small annual licence fee. This gives you full access to the Machine Sentry® platform at a market leading price including our Automated Diagnostic Assistant tool to assist in analysing rotating equipment.