E1 and E11 marked bulbs - BobG
I am currently running 2 cars with "plastic" headlamps. They both take H4 bulbs and I noticed that when I removed a blown bulb it was marked "E1". I have a couple of almost new Philips H4 bulbs from a previous car I scrapped marked E11. Can I use these or should I bin them and get a set of new E1 marked bulbs?
E1 and E11 marked bulbs - jc2
These are just the country codes for the EU country that did the original checks that they meet EU requirements;E1 is Germany-E11 if I remember correctly is the UK.Bulbs should be the same.
E1 and E11 marked bulbs - 659FBE
The "E" numbers are codes for the country of origin as given above. Remember if you have "plastic" (polycarbonate) headlamp lenses, the bulbs should be low UV output, denoted on the box by UV struck out. In practice, most bulbs by high volume European manufacturers meet this requirement, but there have been problems with yellowing of polycarbonate lenses if the UV emission of the bulbs is too high.

Much depends on the value of your car. One of my vehicles is worth nothing and has polycarbonate lenses. It gets Chinese bulbs which work without any problems. I might not risk it with a more expensive vehicle.

659.