The controller has two outputs, the flickering fire effects from each of the outputs is different to the other. The unit can therefore be used with two fires/stoves. Or you could use both outputs with a bulb on each, within one fire to create a stunningly realistic effect. Each output can power 2 standard 50mA dolls house bulbs. Controller size 42mm x 28mm. This product was designed by us and is still currently manufactored by us. We are therefore able to offer full technical telephone/email support if required.