The BlueFlyVario_Bluetooth_USB_v12.3, wanting its button to be pressed, offering to find you a thermal.

Simple

The Bluefly varios measure vertical speed and altitude based on atmospheric pressure. The pressure sensor inside the Bluefly does this 50 times every second, with a resolution that enables the measurement of tiny altitude differences of just 10 cm. Turn it on and it beeps pleasantly when you go up. It is super responsive.  

Pilots

Flight instruments are awesome devices to help pilots know the air. The best components are cheap and the instruments should be too. The BlueFlyVario project grew from a not-for-profit hobby that got out of control. The Bluefly varios of today remain focused on meeting what pilots need to fly. This pilot focused philosophy continues to motivate the production and ongoing development of awesome little varios.

Choose

The Bluetooth_USB model is the latest classic Bluefly that connects to XCTrack or other apps on your phone via bluetooth. The Bluetooth_GPS_IGC adds an onboard GPS with IGC recording. The TTL_GPS is for connecting to xcsoar on a Kobo, and the USB_TTL_GPS_IGC adds some advanced features to it for specific needs.