Black heels

Was listed as sling back heels by another Posher but it looks like there should be straps to them because there is a loop in back. I would need straps for them to stay on. They look brand new..and 3" heel..if you have straps on another pair of heels and they can be removed, they can easily be used with these..I just don't own any as such...says 6.5 on shoe (UK size) which is equivalent to US size 8.5