... . The heater will stop operation automatically when the oil volume of inlet is too low to avoid the damages of the heater ... parts of Tongrui products such as vacuum pump, oil pump and electric apparatus are from SIEMENS, LEYBOLD, OMRON, SCHNEIDER, HYDAC, TONGRUI, AMICO ... lights, tow-eye etc.there are other types of this series depending on your need.if you areinterested in them,please give me ...