S6 is a model number for the head of a light. There is no one part number for it. It can be a vintage 225 series spotlight, a classic 225 series spotlight, 340 Series HID spotlight, AG series decklights or a 275 series rooflight. Without more specific information on what you are looking for I cannot direct to a part number. Would need to know what type of light you are looking for and if spotlight, make model and year of the vehicle.