The bulb glass is tinted blue from a special coating technique, to colour the light in accord with market preferences created by HID and, more recently, LED lights.
The new Xenon Silver headlamps can be ordered as H1, H4, or H7 headlamps. With their silver cover, the H4 and H7 bulbs are barely visible behind the headlamp glass when switched off.
DVN Bonus: As Bosch are presently sourcing all their aftermarket bulbs GE, this bulb is most probably based on the “GE Sportlight”, a product that was supposed to combine more light and bluish effect, of course at the expense of lifetime. But the Sportlight never went on the market on a significant level and the launch did not seem to be successful. Philips launched their X-treme Power bulb and Osram their Night Breaker in 2006, extending the level of maximum performance in legally-approved aftermarket bulbs to the +90% range.
