Planet Bike Bicycle Computers
About Planet Bike - "Planet Bike was born from the heart of a cyclist and our goal is to make innovative, high quality, and practical bicycle accessories. Simply put, we strive to design and develop the best bicycle products in the world."
Some cycling computers can display a power reading, usually in watts. They usually require a separate sensor - in some cases a special hub or crank arm. A few will estimate the value based on speed, cadence, rider weight or other data. "Optional" means it can read from a separate power meter or sensor. "Included" means it is calculated by the computer or includes the neccessary sensor.