2003 Interior Ceiling Vent?
 

I just recently became a Mini owner and I love it! It's a 2003 with only 40k miles. There's a vent-type attachment on the ceiling in the rear before the hatchback. The front (pointing towards the front of the car) cover is missing and the rear cover is vented. What is this thing? I'll order a replacement once I know what it's called.