Boeing 35

I have the 45 and the 55 ( maybe 50) can't remember. I love both. I use the 45 as a carryon and the larger one when I travel by car as my main suitcase. I'm not certain one smaller than the 45 works for much beyond a gym bag. The Boeing is not designed to be used with a strap although you can buy one. Try the crossier (sp?) if you want a duffle with a strap.