... 2) Light weight, small in size, save freight cost. 3) Bulb is directly inserted into ballast, easy installation 4) Wiring harness ... adopted, with heat conduction on the metal shell 7 )Bulb lifespan is 3000hours, ballast lifespan is 6000hours 8) Dedicated ... waterproof rings used to fix bulb and ballast, more tightness 9) easy installation, without connecting ...