In smart mode, you set a desired temperature and then you set a temp range of 2-4 degrees. Seems to be a decent light for the money. I also injured my left shoulder in the military, so I?ve been using these in place of the cheap physical therapy bands I?m always issued by the VA. The Bluetooth is ?eh?. These are barely big enough for my sons baby doll. These slippers also fit very well. My 8 yo son wears a 5/5. Which is usually a Note. Great bottom padding. The newer pair is a night & day difference.