Worked optimally right out of the box. My lighting setup consists of light bars with PAR 38 with LED lamps. Tried to control them through an older standard dimmer. It was completely impossible to gradually adjust the light from zero. The first step jumped the light up to about 50 percent. With my new Botex LED Dimmer, the first step was barely visible and after that, as well as my LED lamps manage, - was stepless. BOTEX LED Dimmer also works perfectly for halogen lamps.