Hella brand is OEM. The glass tends to be more clear with crisper flutes for better beam distribution. The Hella tail lights are way better than others, but you'll pay for it. I got mine at OEVeeDub. Call and they'll swap a set of
smoked lenses with the
housings.
My Hella 911 lenses with modified H4's behind:
My Hella smoked elephant feet:
H4 is a halogen replacable bulb. You can get different wattages of H4. Make sure your wiring is beefy and in good shape if you go with the 100W bulbs or else risk fire.
Blimp has the Hella H4 assembly. Call for bulbs.