Light and smart power meter. It’s the PowerPod, only 50g of weight and can be paired with all the Ant+ devices.
You can easily swip from a bike to another one, you have only to choose beetwen the profile previously setted (road, mtb, ecc)
Automatic setup in less than 5 min
This works with an accelerometer, barometer and Pitot tube and, and thorough an algorithm and 800 measurements do second, you can have the power output.
Here a comparative test with the Garmin Vector: http://euganei.it/euganei/2017/03/test-comparativo-velocomp-powerpod-vs-garmin-vector-2/
Asking half price that is 175€