(open back). When opening the package, these headphones speak of quality. I have a more narrow foot and do feel that they run a bit big. Id highly recommend. Tried other house slippers. My complaint here is that they sometimes seemed to briefly lose sync with each other.  a Mudder Foam Windscreen again, works for me, I just wanted the equivalent of a long t-shirt that covered my butt when I walked around the house but was still somewhat fitted and shapely. The led lights are cool feature as well. I could have it at 100%, put it a way for 2 days, and itll be down to the low double digits.