Saris Fluid 2 Indoor Bike Trainer With Precision Balanced Flywheel TechnologyMake Every Workout Count Better health. Faster splits. More me time. Whatever your goals may be, the Fluid helps you get the most out of each indoor training ride. The large, precision balanced flywheel (with patented fan design) lets you easily customize each ride simply by shifting gears, just as you would outside. This design also helps keep your Fluid working better longer. And thanks to our built to last manufacturing process, the Fluid can help