The rotor inpower 3d power meter left hand crankarm only allows you to record your power readings via your ant head unit inconspicuously integrated inside the crank axle inpower is protected from shocks crashes and outside contaminants plus it allows you to maintain your bikes sleek elegant aesthetics the battery is also located within the bottom bracket spindle image shows a inpower left hand crankarm sophisticated metrics interpret your data through user friendly software and advis