These Chambers are double walled in construction and both the interiors and exteriors are made of stainless steel sheets. An insulated door with leakproof gasket having a viewing window is provided allowing the user to view the interiors without disturbing the test conditions. A hermetically sealed compressor below the chamber is provided for below ambient temperatures. This portion of the Chamber also houses the boiler with an immersion heater fixed with a water level controller for creating humidity. The temperature ranges from 10ºC to 60ºC controlled and displayed with a Microprocessor based temperature indicator cum Controller having an accuracy of ±0.5ºC. Relative humidity ranges from 60% to 95% with ±3% accuracy. All controls are housed in the panel on the top of the chamber. Operates on 220 / 230 volts, AC supply.