If you have a commercially run kitchen then invariably you'll have one or more extraction hoods. The fan used to pull air through the hood will have a speed control to adjust the amount of airflow.
Usually mounted somewhere where they wont be tampered with these generally have an on/off switch and dial to adjust the speed.
The speed control is the weak point in the system, if it fails you lose your extraction and have to shut down your kitchen. You can of course get an electrician to temporarily wire the fan to run at full speed until you can get a new speed controller fitted.
So reliable speed controllers are a must and the fan manufacturers own versions are usually the best. But they're expensive because despite being a critical component the manufacturers know they represent a small proportion of the overall cost of the installation.
Aftermarket speed controllers need not be less reliable than the original equipment but they can be a lot cheaper. Our UF-019 and UF-020 controllers are designed and made in Britain, are drop-in replacements for the leading brand and are shipped with simple to follow instructions. Details can be found on our Products page and they are permanently on sale via eBay.