PowerTuned using PowerTap technology for accurate power readings up to +/- 5% This trainer is designed to fit common road and mountain bike frames with included steel quick release skewer and has three settings for rear dropout spacing: 120mm, 130mm and 135mm Integrated dual ANT+ FE-C and Bluetooth standards Fast response electromagnetic resistance ensures most responsive resistance and maximum power available Robust design is capable of handling up to 1500 watts at 20 mph and can simulate up to a 15% climbing grade Headless mode (powered on, not paired to any apps) lets you ride with a progressive resistance curve that matches the Fluid2 Internally integrated speed, cadence and power data eliminates the need for extra external sensors Internal cooling system moves air through the trainer to keep it cool while active thermal sensors ensure accurate performance data even during the hardest workouts Features clutch knob for perfect roller to tire tension each ride 2` resistance unit roller allows for 650b, 700c, 26`, 27`, and most 29` - up to a 2.0 tire Compatible with a wide variety of devices and virtual training applications, including Rouvy, Zwift, TrainerRoad and many more Over the air (OTA) firmware updates via Bluetooth devices ensures the M2 is up to date ANT+ and BlueGiga USB dongles sold separately Smart Trainer Electromagnetic BlackUPC/EAN/GTIN: 012527018697