FrSky Air Speed Sensor ASS100 ADV (223 MPH Rated)

The FrSky Airspeed Sensor ASS100 ADV works with both Smart Port as well as F.port/FBUS equipped FrSky receivers and measures your aircraft’s airspeed up to 223 miles per hour. Just install the pitot tube away from any propwash or disturbed air, route the included silicone tubing to the sensor and plug into your receiver.

Not only can it send airspeed data to your radio, but with a little work you can set it to warn you of low airspeed, log your highest speed or even silly stuff like automatically drop your landing gear below a certain airspeed.