The slip on is a great idea, they are super cushie and the length is right on.  They have a nice high toe box.  However, the double wide is more like a 4E.  I ordered them for my Mother who wears an extra wide and they fell off her feet.  They sounded like flip flops.  We kept them and am taking them to our shoe repairman to see if he can address the width issue.  They were a great buy at $20.