paragliding-bazar.cz
https://www.blueflyvario.com/product/blueflyvario_ttl_gps_v22/ BlueFly Vario in a variant designed to connect to a Kobo reader or similar device. It contains a beeper and a GPS receiver, it sends position and bar data via UART to an external device. As a classic beeper, it can also work independently, just connect the power supply. I was converting my Kobo Nia to a LK8000 glider nav, but my unit usually started restarting after a few minutes of flying in direct sunlight, so after a few tries I gave up and switched back to XCTrack on mobile - so I was left with practically new (within 20 minutes in air) BlueFly...
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