The Smscom 4.5Amp twin fan speed temperature controller is a great piece of kit that automatically controls the speed of your intake and outlet fans to maintain the temperature that you set. The Smscom twin fan speed temperature controller has a temperature sensor on a flying lead which can be placed in the grow-room in an appropriate place. The Smscom twin fan speed temperature controller has two mains sockets under protective flaps on the front. One socket is for the intake fan, the other socket is for the outlet fan. The user has 3 controls to set on the front of the Smscom Twin Fan Speed Temperature Controller. The first control allows the user to set a minimum fan speed. This allows the user to set the lowest fan speed required for adequate air exchange in the garden space, even if the temperature goes low. The second control on the Smscom Twin Fan Speed Temperature Controller allows the user to set the desired temperature to be maintained. The third control allows the user to increase the amount that the outlet fan runs compared to the intake fan. This maintains a "negative air pressure" ensuring that air always leaves the room via the extraction fan and not through gaps around doors etc. Once the Smscom Twin Fan Speed Temperature Controller has been set up and switched on, it will find the ideal fan speeds to maintain the temperature set by the user. This process initially takes the Smscom Twin Fan Speed Temperature Controller several minutes as it "learns" how much the fan-speeds affect the temperature in your particular grow-space using your particular fans. The fan speeds will never go below the minimum set by the user, even if goes cold. This ensures that your plants will get the fresh air they need to grow, no matter what the air temperature is.