Peltier heating/cooling thermostat with a temperature range of 5-85 °C. Big compartment room for 4-5 HPLC columns with a length of 350-400 mm as well as space for valves, precolumns and column switch valves. Programmable via alphanumeric keyboard or RS 232 interface. The temperature control allows isothermal steps and linear gradients for up to 99 temperatures. With two-way forced-air circulation and double sensor reference technology, that means very good temperature distribution, temperature stability and repeatability.