Lately we have gotten the question “Which MSpeed sensor do I need?” The answer is – well dependent on you. Both the MSpeed and Mspeed450 use dynamic pressure to measure the true airspeed of your model via a pitot tube. Where they differ, is in the measuring range. The MSpeed will measure airspeed from 25-350 km/h ( 15-215 mph) and the MSpeed450 will measure the airspeed from 80-450 km/h (50-280 mph). So, which one you need, will depend on how fast, or slow, you are flying.