Varilight Dimmer Switches have an industry-wide reputation for exceptional performance, long life and innovation at attractive prices. Like all Varilight products these V-Dim (Standard) Series dimmers are designed to meet the latest European Safety Legislation. It is important to select the correct dimmer switch for your application so please read the following information carefully. The lights are dimmed by a rotary control knob and turned on and off by a push on/off action. V-Dim Push on/off dimmers are suitable for 1-way and 2-way circuits. Our V-Dim Series Standard Dimmers are Leading Edge and can be used with mains voltage lighting and good quality Low Voltage Electronic Transformers. When using Electronic Low Voltage Transformers we recommend that a maximum of 5 good quality dimmable Electronic Transformers are used (10 if Varilight) with this Dimmer range. The V-Dim switches are not suitable for use with LEDbulbs. Dimmer Knob Manufacturer Code  DOU-HQ4W Manufacturer DESC.  HQ4W