Hid ballast Use the top grade ir mos( most of other supplier use the bt mos). Have the cold /hot change testing(-45-125 degree) and vibration testing, no rule shaking(simulate the car in the different place) also the drop testing. All the testing can make sure that we have the top quality of all ballast . 1.The world initial without concussion start, lasted two times of the bulb life span. 2.High bulb voltage decline function which hella product cannot have. 3.We use the top grade ir mos. Most of other supplier use the bt mos. 4.Also we have the cold /hot change testing(-45-125degree)and vibration testing, no rule shaking(simulate the car in different road). 10.5*7.7*3.2 cm