The units are composed of AC series compressors manufactured by the advanced technology and equipment imported from Arctic Circle, UK, high efficient condenser, liquid tank, dry filter, pressure meter and controller and so on. AC series units have the following features; 1.The air- cooled condenser is the high efficient brass wing type; 2. The hell tube type water- cooled condenser adopts high efficient rib type heat exchanging tube with water covers on both ends easily dismantled and cleaned; 3. The air- cooled condenser adopts special fans of Grade 4 and 6 which have the advantages of efficient and optimized design, full role of heat exchanger and low noise; 4. The separate unit and V type air-cooled condenser of the optimized pressure control can ensure the energy-save and low noise. The V type condenser discharges air upward, so it can be installed against wall and save pace; 5. Compact structure design . The unit's matched with high and low pressure controllers and high and low pressure meters, controlling and monitoring the operational pressure of the unit. AM, AR compressor units are matched with oil pressure difference controller and oil separator. The medium and low temperature units are matched with gas-liquid separators. The water-cooled units are matched with flowrator. 6. The units can work under high pressure (2.4MPa). The liquid tank and water-cooled condenser of AM,AR compressor units are matched with safety valves with the protection value of 2.4Mpa , making the units reliable and safe. 7. The medium and low temperature units are matched with computer controlled power panels, ensuring the automatic temperature control and defrosting. The control circuit can effectively prevent voltage lost, phase lost, overload and hampered rotation. The compressors have strong