This free-download version will provide 10 trial sessions before committing to a subscription plan. You can purchase Dental RPM Pro in Google Play for an ad-free personal version. Dental RPM Plus is a high speed acoustic rpm meter fully capable of measuring high speed air-driven handpiece free running speeds up to 550, 000 rpm. Its capability in electric handpiece rpm has not been fully explored. At this time, this app is not recommended for electric handpieces. Dental RPM Plus makes very accurate measurements of high speed handpiece rotational speed with its proprietary frequency analysis algorithm that distinguishes the sound corresponding to the shaft rotation from other noises generated during handpiece operation. Even in a situation where multiple handpieces are operating simultaneously, it correctly captures the nearest handpiece's rpm. The app also reports the peak noise level (A-weighted) of handpiece at the time of measurement. This app is compatible with all Android devices with Android OS version 2. 2 or higher. A patent is pending on major features of the app including its functionality and frequency analysis algorithm. Features- Steady-state speed in revolutions per minute (rpm) between 25, 000 and 550, 000 with an accuracy of Ã?Â±2584 rpm within 10 cm to 3 m (4 inches to 10 ft) distance from the handpiece. A-weighted noise level with an accuracy of Ã?Â± 3 dB. Recommended distance for dental handpiece noise measurement is 45 cm (18 inches) from the head. Hold button to freeze the reading (hit again to resume). The app will display 0 rpm upon launching. Hit "Set dB" button to start (while handpiece is not operating).