The rowing machine incorporates many muscle groups at once, creating a great workout. ・Magnetic rower The magnetic rower uses a maintenance- free magnetic break system to create resistance. The magnets are incorporated into the flywheel. They adjust resistance in calibration with your pull and are set. ・Air rower The air rower has a flywheel that creates air resistance as you pull against it and can be calibrated to increase or decrease resistance. The air resistance also goes against the force being applied, therefore, the faster you pull, the harder the resistance. The design simulates rowing in water, with a fluent and natural motion. Please specify “Magnetic” or “Air” resistance rower, the power source voltage when ordering.