Varilight V-Pro Series Classic White Plastic, 4 Gang (Quad), 1 or 2 Way 4x120 Watt Push on/Push off (Trailing Edge) Dimmer with White KnobsEliminate Dimmer Buzz For GLS Bulbs, GU10 Lamps, and LV Transformers Including Trailing Edge Loads. The V-Pro Series Dimmer has Soft Start Technology, allowing a longer life span of the bulbs or lamps used by increasing the brightness level softly, which also creates a welcoming effect.  The V-Pro Series were primarily designed for Dimmable LED\'s, the dimmers, with a minimum load of only 10 Watts, can operate at least 1-20 good quality Dimmable LED\'s. These Dimmers can also be used to operate up to 12 Varilight (YCA20D) or Megaman Dimmable Energy Saving Lamps, (Please refer to the instruction leaflet of the Megaman lamps for usage tips). The V-Pro Series Dimmers can also be used for Mains Voltage Lighting, Trailing Edge Loads, and Electronic Low Voltage 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. Please note: add the watts of the bulbs/lamps if using Varilight Transformers, to determine which dimmer to select, but if using another manufacturer of transformer, add up the VA of the transformers so it does not exceed the maximum of the dimmer.  The V-Pro Series Dimmers can also be used for mains incandescent GLS lamps (standard mains light bulbs), GU10 Lamps or similar Hi Spot Mains Halogen lamps, (only use quality UK supplied lamps), up to the maximum load as specified on the dimmer. The V-Pro Series Dimmer can NOT be used for wire-wound Low Voltage transformers, Fans or inductive loads.