My VW Polo 6R left tail light is off and it seems there are several kinds of bulbs available for purchase:
12V 5W
12V 12W
12V 5W + 12V 12W
12V 12W + 5V 5W
...
My first guess is that the 5V is just a mistake on the listing. But what are the bulbs that are listed as a combination of 5W and 12W for ? Do they draw different currents when the engine is on/off ?