A modular water bath system is specifically designed to maintain precise incubation temperatures as required by the various regulatory coliform test methods. The highly flexible water bath system enables the selection of the optimum size tank and lid and then adds the special immersion circulator that has been programmed with three preset temperatures: -35.0°C, 44.5°C and 45.5°C. It features microprocessor control for maintaining temperature uniformity and stability. Push-button selection of preset temperatures makes it easy to set the temperature required for a particular test method. A wide choice of tanks is available with capacities ranging from 5 L to 38 L in stainless steel and 5 L to 18 L in plastic.