Fluid Resistance: The proprietary Fluid in the JetBlack Fluid Trainers increases resistance exponentially, the faster you spin the harder it gets. Correct use of your bicycle’s gears will allow you to fine tune any training session without having to manually adjust resistance. When used with the full range of JetBlack sensors, you can enjoy training sessions identical to those used by professional cycling teams. Fluid resistance trainers provide a more ‘road-like’ feel than magnetic trainers and this feel is increased by our weighted flywheel. Our weighted flywheel and patented fluid resistance unit provide a progressive resistance level up to 900 watts.