Cycle-Ops rollers allow you to practice skills while riding indoors, so you can get serious about your form at any time of year. The solid steel frame construction, extra wide stance, and 6 floor contact points, allow you to ride with confidence and get on and off your bike easily. CycleOps? precision roller drums make for a smooth and quiet ride. The bi fold design gives you convenient storage and transport. Precision-lathed 3.25? aluminum rollers will not distort when exposed to heat or sunlight. Lowest profile on the market, folds for easy transport. Fully assembled. For indoor or outdoor use. Truly sealed bearings. Lifetime warranty. Without resistance