2001 Volvo V70 rear tail lights/rear fog lights

The 2001 Volvo V70 has a feature (factory option?) that allows one to turn on rear fog lights, which are basically really bright tail lights. The rear fog lights sit behind red lenses, and are just above the reverse lights (back up lights).

The Volvo part no. is 989823-0. The actual bulb is an Osram bulb, which has the following markings: Osram 3K 7225 LF 12VP21/4W

It is a two-filament bulb, one of which is 21 watts and the other is 4 watts (I think).