Helps with comfort and may save a pair of shoes you had thought of throwing away
I started off by putting all four pieces in a pair of black pumps and these made it hard for me to fit my feet in the shoes comfortably (the shoes were kind of tight to begin with).  Truthfully, I don't really feel like I need the heel pieces.  However, I really love the part that goes under the front of my foot.  It adds a cushion and it has a ridge to prevent my feet from sliding to the tip of the shoe (and, thereby, help prevent my toes from getting crowded in the very tip of my pumps).  I had another pair of shoes that are heels and open-toed sandals that had given me blisters on my pinky toes because my feet kept sliding forward and rubbing on the sandal band (that crosses over the toes).  I put the pieces of the kit that go under the front part of my feet and it did feel like it helped keep my feet from sliding forward so much---so now I don't feel like I have to throw these shoes away after all (although I'll still have to try wearing them for an entire day and see how they fare, but I have hope).  The other good thing about this kit is that the backs of the pieces are sticky so the pieces stay in place, but it's not too sticky, so I can remove the pieces and put them in other shoes.  I did receive this kit at a discount in return for my honest review, which I have provided.
Rating: 4 stars