D2, D2S, D2R, D2H... what's the difference? If you're doing a retrofit with a D2-type projector, you know there's many options of D2 bulbs on the market. D2S is the size used in projector lamps, while D2R designates use in reflector-style headlamps.

D2H HID Bulbs | Diode Dynamics

All standard D2S and D2R bulbs have a socket-style connector on the base. To power them up, you can use a D2S Ballast, just like what you'd find in a factory headlight. These are HID ballasts which have a socket on the output, specifically for D2 bulbs. However, these ballasts are often slightly more expensive, and they're specialized for use only in D2 setups.

Hylux D2 HID Ballast

You may want to use a standard HID ballast to power up your D2S bulbs. Problem is, standard aftermarket use AMP-style connectors. If you find yourself with standard ballasts and D2S bulbs, you can purchase a set of AMP-to-D2 adapters. With a pair of these, you can essentially add the required socket to your standard ballast, and successfully plug them in to the bulbs! However, be careful on where you purchase them - cheaper adapters often result in a loose connection, which can cause problems in lighting up the bulbs. Adapters have a bad reputation for this reason, but a quality set will work well.

D2S Bulb Adapter (pair)

What if you don't want to bother with sockets at all? After all, the socket requires more room behind the projector, and it may be tricky to get it installed on the bulb, and locked into position once everything is installed on the vehicle.

D2H bulbs are an aftermarket invention, that eliminates the socket altogether. They are built with wires coming out the base, leading to AMP-style connectors. They can be connected directly to a standard AMP HID ballast, with no need for sockets. No socket also means lower clearance, and potentially more room where you need it.

D2H HID Bulbs

At Diode Dynamics, we offer D2H bulbs in a variety of color temperatures, including 3000K, 4300K, 5000K, 6000K, and 8000K. They have ceramic bases, for accurate alignment, and are tested in-house to ensure true, accurate colors without any hints of green like many cheaper bulbs on the market. With over a decade of experience, Diode Dynamics can help with your next lighting project!