SMS Hybrid Fan Controllers This fan controller combines mechanical fan speed control with cutting edge digital temperature sensing. Robust construction, temperature probe with 5m lead and simple operation together with no humming or buzzing makes this the choice for the professional. This hybrid controller will operate most fans, apart from EC fans and is favoured mostly by the Isomax fan users. It will ensure smooth running of the Isomax and its longevity by not damaging the internal workings of the fan. Not only can this controller regulate the temperature, it can clear high humidity levels in late flower to help prevent mould through its light sensor. How it works Plug your small or lesser powered fan into the left hand socket as you look at it. The bigger more powerful fan into the right hand socket. Set the minimum fan speed with dial one (the left dial as you look at the unit), for example 1. Set the desired temperature with dial two, for example 26. Set the maximum fan speed with dial three (the right dial as you look at the unit), for example 5. Place the temperature probe at the top of canopy, not directly under a light and away from any direct air flow. Hang the light sensor near to a light, do not yet remove the cap. Plug the unit in to the power source. If you want to use the Pro function remove the cap. This will initiate the fans to come on in the night cycle every hour for 7 minutes one step above its current setting clearing the room of any humidity that may have built up. By only running one step faster than the what has been set on the controller it ensures that as much as the heat as possible is kept in the growroom, which is great in the winter months and because high humidity problems normally happen in the night cycle, when the light come back on again the Pro function will switch off and the fans run as normal. If you you do not want to use the Pro function, simply keep the cap on the light sensor, normally you would keep the cap on in the vegetative stage and early flowering stage. Completely Silent Fan Speed Operation Highly Accurate Temperature Control Can help reduce humidity levels 5 Meter NTC Temperature Probe Very Simple to Use