The foam heads fit to velcro backing plate and are used with different grade polishes to achive different results. You can also fit Microfibre bonnets / wool over the hard foam heads to help with buffing.
I have not had good results with the buffing bonnets though.
The issue with using a non DA buffer is that you run the risk of inducing hologramming into the paint as the head spins in one direction. Thats a quick summary anyway.