This is a black magnetic nano cache - about the size of the tip of your pinky finger and room for a log only (BYOP).
It is right in south downtown Atlanta - a very muggle-heavy area, which is why the difficulty is a 2. Please use stealth when finding and replacing (and note that the magnet doesn't stick very well).
I think that there are plenty of pay parking lots nearby and metered street parking, but I never try to park down here. MARTA is your best bet; the cache is a couple blocks from the Five Points station.