sizing for nikes are all over the place, in part because they've started in the last year or two to fix the narrowing of their shoes. BF II's run true to size. Resolves are wide, running a little bigger. The oscillates come from another generation, hence running smaller. I wear a 10 in the BF Ii's, a 9.5 in the resolves and a 10.5 in the oscillates. Never tried the vapors.