It's been hit or miss for me. I succesfully stretched a few pair but there was one bair of booties that just did not want to give. You may have to try a few times experimenting with how many turns of the screw thing you need. The instructions will tell you not to turn the screw more than twice but two turns does nothing! I cranked it a good 8 times to get a good stretch but I was a little worried that I might ruin my shoes. I guess my advice is to be careful.