1. with mirror surface in stainless steel,foursquare semidrde transition,shelf support handling freely,easy for deaning within the case. 2. choose newhandling of fuzzy logic controller,fast to set value,accuracy and stable in operation. 3. international brand compressor and circulation fan,environmental protection cryogen(r134a),with high efficiency and lowpower consumption,prom oting energy saving. 4. independent temperature-lim ited alarm system can autom atically interrupt when it is over limit temperature,ensuring the safe operation of the experiment,with no accident(option) 5. 4~20ma standard current signal,rs485 interface may link grapher and calculating machine.(option) 6. there is a 50mm instruction connection hole on the left side of the casem,easy for testing operation and temperature measurement.