The model 9300A series of Temperature Controlled Chambers is designed as a convenient and inexpensive way to maintain the temperature of air resistors in the calibration laboratory. It is large enough to house several standard air resistors and features two adjustable shelves to permit easy access to the standards. The shelves are easily removable.

Easy access to the inside of the chamber is achieved through the conveniently mounted front door. Resistor leads are brought into the chamber through a small, insulated opening in the rear of the unit. The integrated control unit adds convenience as it eliminates a separate controller unit. Temperature control is located inside the chamber. A keyboard control can be used to set the individual temperatures between 15 °C and 40 °C, or the temperature may be set over the GPIB.

Cooling and heating for the chamber are provided for by a thermoelectric Peltier element using internal thermistors as sensing elements. Internal fans are used to move the air inside the chamber to provide for better temperature stability and uniformity while maintaining a quiet operation. The internal temperature is shown on an external display located on the front of the chamber.

The Over Temperature Protection (OTP) has 4 selectable ranges.