Thanks Trek, that's it! It's the Bones 2 and I love it. It never comes off the back of the car because 1. it's a pain for me to get it tightened back on securely and 2. my bikes are always on it.
The one thing I would recommend is to put a sock (or soft cloth) over the part that rests on the top of the trunk. It marred the paint a little, but not bad.