So-Low 3503 CO2 Incubator offer dependable Infrared (IR) CO2 Sensor control and are ideal for QA/QC applications. The compact size of the 3503 conserves valuable lab bench space. The six gallon water jacket and intelligent microprocessor offers superb uniformity for even the most demanding incubations. The SHEL LAB CO2 Incubators now come with a 5 Year Limited Warranty. The new look of the 3500 series of incubators includes great new features such as an anti-corrosion anode allows the use of distilled or tap water (de-ionized water should not be used) in the compact water jacket. Anti-contamination features make cleaning a breeze and the CO2 sample port has been moved to the front control panel for quick and easy access.