Oscilloscope Pro 2 is a free oscilloscope app developed by NFX Development for Android devices. It allows you to analyze signals from the device's microphone, whether it's internal, external, or Bluetooth (on some devices, a USB microphone will also work). The app features advanced and simple touch gestures to scale the viewable area of the graph, tap to pause and resume measurements, and a 1-second recording buffer. Additionally, the app provides average frequency readings for accurate signal analysis.

The app's extras include in-app payments for saving and recalling previous signals from file, advanced signal triggering with auto/normal/impulse in either rising, falling, or both directions, and optional measurement markers for ease of reading. However, the app's basic features are sufficient for basic signal analysis. Overall, Oscilloscope Pro 2 is a useful and user-friendly app for anyone who needs to analyze signals from their device's microphone.