I normally love FitFlops but this pair I do not.  When I put the new pair of Classic Electra FitFlops on, I noticed my feet would try to slide out from under me.  This happened on a variety of floor surfaces.  When I compared them to an older pair that I have been wearing and to the others I have; I noticed the sole of the shoe is completely different material.  All the others I have (and I have several different styles of FitFlops) have a rubber sole, this pair did not.  I bought them the last week of February and waited for the weather to warm up to wear them.  I missed the return window by two days.  So be sure to check your purchase to make sure it works for you before the return window closes.  (I did try this shoe on; more than once, just to make sure I wasn't imagining the sliding.)  It wasn't my imagination.