Zhengzhou Greatwall Scientific Industrial & Trade Co., Ltd. is a comprehensive company, whichhas developed teaching instruments and equipment including water circulating type multipurpose vacuum pump, low temperature cooling liquid circulating pump, low temperature cycling pressure pump. Low temperature(vacuum)pump. Digital-control super low temperature constant temperature slot. Chemical reaction experiment device. Digital display direct-current stepless speed adjustment treater, glass container quick baker, digital display small vacuum dry box, freezing vacuum dry box and electric heater.