fx12 is the companion app to fx12, fxRDT and fxWS devices. It provides a interface to view & change parameters of fx12 and fxRDT, including altimeter & GPS data in realtime. The optional Apple Watch app shows the realtime telemetry and allows you to RDT the model.
This app may use your location even when it isn’t open, which can decrease device battery life. Continued use of GPS running in the background can dramatically decrease battery life.