bility slightly varies between±2°C, Warning device for temperature upper limit is installed to protect heating wire.?3.It has the functions of synchro drive of the upper and lower wheel chain, auto compensation, and auto reverse.?4.Double pedal control is designed according to human mechanics, simple and comfortable, suitable for long-time operation.?5.It is possible to work 24 hours continuously with high efficiency.?6.Blowing-in wind can be filtrated without oil or water by unique heater