Not sure it is worth it
I did the research...I bought the metal vs. plastic mechanics. I used the stretch spray. I kept them in overnight. They jammed. I had trouble getting them out of my shoes because they jammed. Thank goodness I did get them out, that would have ruined it for me for my daughter's wedding. When it was all over, the shoes didn't feel like they had been stretched at all.
Rating: 2 stars