Stratus 3 (by Appareo / Stratus) is a portable ADS-B receiver that provides subscription-free weather (FIS-B), dual-band ADS-B traffic (978 MHz UAT + 1090 MHz ES), WAAS GPS, built-in AHRS (backup attitude), and flight data recording. It works wirelessly with apps like ForeFlight, Garmin Pilot, Stratus Horizon Pro/Insight, and others.