This kit is for people who want even more Brightness than the single kit! Each kit comes with everything to illuminate one footwell or other section of the car...If your doing both footwells you will need two kits. Best part of this product is that it runs off of 12vdc. Thats the same power your lights are running off right now! So you can just tap right into any 12volt source on your car. (They are everywhere: Your excisting lights now, lighter adapter, even your radio is 12volts) *All of our automotive kits now include a specialized mounting kit complete with all the hardware necessary for the simple installation. Available bulb sizes are 6" and 12"