Construction All cabinets have stainless steel interiors fitted with adjustable shelves. All SF models have sealed chambers making them suitable for humidities up to 98%. SF models can have an outer door heater (extra cost option) to demist the inner glass doors. CFC-free polyurethane insulation provides very efficient thermal stability in all models. A 12mm access port is provided as standard. Temperature Control Monitoring and control of both heating and cooling functions is performed with great accuracy, and achieves typical temperature stability of ±0.5°C. The microporcessor based digital display allows the temperature performance to be easily verified. A digital over temperature safety cut out is fitted to all models.