On this page:
http://www.sylvania.com/ConsumerProd...g/HighPerforma
nce/Silverstar/ProductLine/ it lists Silverstar products, including the
H4ST halogen bulb recommended for Motorcycle use.

However, on some of your other pages, you tout the new and improved
ULTRA Silverstar product line, that doesn't appear to be referenced at
all on this product matrix. You do have a 9003 ST, but I don't see a
9003 Ultra, which on other sites claims to be an H4 replacement.

If I have an H4 bulb in my motorcycle, which one of these bulbs will be
the most efficient, brightest, and longest lasting bulb available from
your company?

Thank you for your inquiry. Our e-Marketing group is working on
updating our website to include more information on all of our product
offerings.

The brightest and whitest version of part H4 (also known as 9003) is our
SilverStar ULTRA, sold under the part number 9003/HB2 SU; however,
because these lamps are significantly brighter than standard halogen,
they will have a shorter life span. They are rated for approximately
200 hours of use.

The longest lasting version of part H4 is our in our Long Life product
line, part number 9003LL. The LL product is rated for approximately 800
hours of use but is no brighter than standard halogen.

Hi, thanks for the reply.

However, I'm wondering does that hold true with motorcycles, as well as
other vehicles? As I said before, the H4ST specifically states on your
site that it is recommended for motorcycles.

Are either the 9003/HB2 SU or the 9003LL specifically designed for use
in motorcycles, w/ the increased vibration, etc.?

And where does the H4ST fall in compared to the above 2 products in
length of life in a motorcycle? Is it brighter than the LL, while having
a longer life than the SU, being a compromise between the 2?

Please be as detailed as possible, I'm sharing this info w/ many people
also considering changing their head lamps on their motorcycles.

In short, 9003 and H4 are different names for the same part. If you were
to remove parts 9003 and H4 from their packaging, you would find that
they are exactly the same part, right down to the part number branding.
We used to manufacture parts 9003 and H4 using different filaments; part
H4 was made using more robust filaments than part 9003, making it better
able to handle the vibration of a motorcycle. Several years ago the
filaments used to make part 9003 were changed, and we now use the robust
filaments for both parts 9003 and H4. The parts are still sold under
separate part numbers because they have always been marketed that way.
American automobile manufacturers tend to use the 9003 designation;
European automobile and American motorcycle manufacturers tend to use
the H4 designation, so we package this part using both part numbers 9003
and H4, but they are one in the same.

The regular SilverStar (ST) product is rated for approximately 150 hours
of use. We developed the ST product first. We were able to increase
the color temperature and light output slightly while at the same time
increasing the life span by 50 hours, and thus the SilverStar ULTRA was
introduced.

Please let me know if you have additional questions.