The FreeStep is an aerobic recumbent bicycle machine with ZERO impact. Great for ANY recovery to your own wheels as in knees, hips, ankles, back, etc. I wish it recorded hours of use because it's been VERY lightly used. I used it while recovering from arthroscopic surgery on my knee. We're moving and don't have any room for it. YOU get a very nice deal. It's selling for $749 right now on their website, so getting this machine for way less than half is a steal.