H4-3 All in one ballast Advantages:

 1 slow start with no inrush current, extend the bulb life two times.
2 starting current of the cold bulb less than 6A.
3 starting power of the warm bulb less than 35w.
4 starting power of the cold bulb less than 55w.
5 in the case of vibration,the power change less than 3w (others are 17w)
6 rated power is very stable
7 after the bulb aging, the bulb still lights up even if the bulb voltage drops to 150v, others wont light up when the bulb voltage drop to 123v.
8 output frequency is 370HZ, reducing the electromagnetic radicalization

http://www.hmhid.com