This is an Ideal brand lamp socket dimmer. This dimmer screws in to a standard base lamp socket and will dim up to a 200 watt bulb. This dimmer will add about 1 inch of length to the bulb. Easy adjustments with knob on front of dimmer. You can continue to use your existing on/off switch to turn light on and off. Ideal part number is 56-070 and these are new and in original packaging.