Yellow glass decorative head for H4 bulb.
We have tested this decorative head on an Osram H4 bulb (that you can fond in the shop). We cannot guarantee that it will work with all H4 bulbs as there are some slight differences from one manufacturer to another.
Check that there is no edge between the glass part and the metalic part of the bulb. See the example on the images 5 and 6.