The new state-of-the-art diamond reflector has been computer engineered to produce a perfect spot from a 51 head. The diamond reflector will eliminate the "dead spot" in any bulb. Because of its careful crafting, it will create a perfectly round, white beam of light that will be sure to outshine all others. This item has become a "must-have" in the headlamp industry. The reflector will only fit the H1 or H2 head and is not compatible with other low-quality 51 heads.