If you own a late model Honda, Suzuki or Kawasaki, look at the bulbs. If the looks like a standard H4, but are stamped 45/45 watt, you will need these shims for proper installation of any new standard H4 headlight bulbs.
These shims are laser cut stainless steel so you will never need another pair! You can see in the photo below the two sets of tabs at the bottom of the bulb. You must trim off the bottom 2 tabs so that the bulb will go into the housing. Here is where the problem lies; doing so actually causes the bulb to point up, not straight as needed for proper light disbursement - these shims correct this problem. Upgrading your bulbs without the use of the shims can actually REDUCE your light output!
Known applications: Honda ST1100 (all years), VFR750/800 (1994-2000) and 1998-2000 Goldwings.