The Bath/Circulation thermostat E 306 (Lauda GmbH, Koenigshofen, Germany) allows to heat a water bath (5.5 liters) to maintain the water at the desired temperature (Internal Control Mode). Moreover, it can be used to pump the heated water in a external, closed tubing circuit (External Control Mode) and regulate the water temperature in the bath according to the reading of an external temperature probe (Pt100 type). The controller is a cascade controller with Proportional-Integrator strategy, with all the controller parameters tunable by the user according to the particular application. The pump is a pressure pump with choice of 5 different output steps (maximum flow rate: 20 l/min). The bath houses a gas humidifying module (H101-HM, Okolab S.r.l., Ottaviano, Italy), constituted by an heating coil and a bubbling bottle with a filter candle, immersed in the heated water.