It is a hitch-mount type.

We've only used it once but so far so good! We opted not to get a roof rack because 1) I'm an upper-body weenie strength-wise and challenged height-wise so would have had difficulties getting the bike up there and 2) We've got a garage and with my luck I'd decapitate the bikes on the way home.

DBF didn't want a trunk-mount rack because he heard it scratches the paint and then you can't open the trunk.

This one supports the bikes by the wheels and that arm thing ratchets over the front wheel. A guy at the LBS said carbon frames shouldn't be suspended by their top-tubes. The bikes don't touch each other at all.

Hope that helps!