When investing in hid kits you would like to use latex safety gloves so that you do not contact the glass with the bulbs using your fingers. The reason is , the simple fact oil out of your skin can limit the lifestyle with the HID bulb.
Xenon H.I.D. (High Intensity Discharge) lighting is a superior lighting technology. Instead of having a filament inside the bulb, it is replaced with xenon gas. When the xenon gas ignites, it produces a vivid and bright light that is 3X more powerful than that of a halogen bulb.
Xenon gas-filled bulbs and other halogen ‘xenon’ bulbs are simply a standard halogen bulb that is either coated with a blue film on the outside and/or filled with a gas to imitate the look of a true xenon HID bulb. These bulbs produces much less light than xenon HID bulbs and often less than that of a standard halogen bulb. Xenon gas-filled bulbs also suffer from a short 6-month life-span.
This technology also allows for the bulb to ignite at a higher color temperature: which gives it the white / blue coloration.
All that feature and technology make more benefits for travellers.
article source : http://www.ebay.com/gds/Difference-between-Xenon-HID-and-Xenon-Gas-filled-bulbs-/10000000004613590/g.html