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 135mmIntegrated dual ANT+ FE-C and Bluetooth standardsFast response electromagnetic resistance ensures most responsive resistance and maximum power availableRobust design is capable of handling up to 1500 watts at 20 mph and can simulate up to a 15% climbing gradeHeadless mode (powered on, not paired to any apps) lets you ride with a progressive resistance curve that matches the Fluid2Internally integrated speed, cadence and power data eliminates the need for extra external sensorsInternal cooling system moves air through the trainer to keep it cool while active thermal sensors ensure accurate performance data even during the hardest workoutsFeatures clutch knob for perfect roller to tire tension each ride2` resistance unit roller allows for 650b, 700c, 26`, 27`, and most 29` - up to a 2.0 tireCompatible with a wide variety of devices and virtual training applications, including Rouvy, Zwift, TrainerRoad and many moreOver the air (OTA) firmware updates via Bluetooth devices ensures the M2 is up to dateANT+ and BlueGiga USB dongles sold separatelySmart TrainerElectromagneticBlackUPC/EAN/GTIN: 012527018697