These are a replacement for my old fins…which just happened to the same type, only 10 years old (and purchased from same place)! Apart from being slight longer and wider, they have kept with the same proven design. Am looking forward to getting another great 10 years of use out of these ones! For what its worth, I tried a non split fin for a couple of dives but just didn’t like them as much, so I went for the new version of the ones I had been using all those years. And am I glad I did!