The Precor 846i-U Experience Series has a double-step-up drive and magnetic, no-contact generator system. The 846i-U cycle moves smoothly and quietly, with less maintenance. Belt Drive System: A double step-up drive gives users a smooth, quiet exercise experience. A Poly-V belt is used instead of a chain which a quiet ride every time. The 846i-U exercises all leg muscles. Users can also stand on the pedals like climbing a hill on a traditional bike. Tactile paddles control resistance, confirming user input with a satisfying click. The multiple feedback options make it easy to monitor workouts. Additionally, the seats are designed for comfort across a wide range of body types. The upright seat has a ratcheting system for easy adjustments.