Cycling power meters generally need to be affixed to the crank with wire ties, magnets, brackets or double-sided tape. The StageONE from Stages Cycling is a power meter that comes pre-installed on the left crank arm component of a bike. It uses a strain gauge and an accelerometer to capture power output data, which is transmitted via ANT+ and Bluetooth to compatible cycle computers and smartphone apps. Most important of all, it's makers claim it's cheaper than existing cycling power meters on the market.
Read the full article: StageONE cycling power meter comes pre-installed on crank arm