TRANZX is a manufacturer of high end bike components, and produces a range of quality indoor trainers. The JD113Q trainer uses Magnetic resistance allowing it to be smooth and very quiet. It is an excellent value, performance indoor trainer for those who are serious about stationary trainers. Ideal for working out at home or warming up before a race. The JD-113Q indoor trainer does not feature adjustable resistance. The trainer is pre-set at medium/hard resistance. A replacement quick release skewer is included allowing you to exchange your lightweight alloy skewer and prevent it from damage when using the trainer. Features: •Suitability: Fits all road and mountain bikes (26", 700c & 28") •Resistance: Extremely Powerful Magnetic, smooth and quiet •Construction: Steel •Weight: 8.5kg •Colour: Red I have used this only twice.