H4 size is available for both HID and LED systems.
HID H4 bulbs are carried in three types: single beam, Bi-Xenon and Low/High Halogen bulbs.
Regarding LED bulbs, H4 is only available in dual-beam option (High and Low beam in one bulb).
These products are designed to meet the requirements of those who want to have they car lights as bright as possible.
To make sure that this is the correct bulb size for your car lights, you can look it up on the bulb itself or in your car owner’s manual.