Wrong fit – AUTODOC: buy quality car parts Review

My rims arrived perfectly, but my K and N air filter was the wrong size and fit- even after I entered my exact car model. I was told that since I mounted the air filter already, they cannot take it back. HOW COULD I DETERMINE IF THE SIZE WAS CORRECT OR NOT WITHOUT FITTING IT?
Review by CJASSASTY on AUTODOC: buy quality car parts.