This is a Varilight Polished Brass 4 Gang 120W Professional Series 2-Way LED Dimmer on a flat plate
If you're looking to use a dimmer on a 2 way system, please note, 2 dimmers will not work together as this will cause a conflict in the circuitry. A dimmer will only work on a 2 way circuit if a standard rocker switch is being used on the same circuit.