HPLC column warmers are designed to allow to keep your columns at a constant temperature (known as isothermal) or utilize a series of temperature increases and constant hold temperatures (gradient elution). The use of HPLC column heaters allows for the separation process to be controlled and optimized, as heat generally reduced the time needed for separation. The amount of heat can generally be altered between a range of just above ambient temperature to over 300 °C. The heat you use will vary dependent on both the sample components and the stationary phase of the column.