Promising review: "Oh...my...soul. This product is a miracle. I have VERY blister-prone feet, and it is so difficult for me to find shoes that don't rub me raw (I'm talking every kind of shoe — flats, sandals, heels, tennis shoes, etc.). I bought new water shoes that were supposed to be amazing for your feet, and they felt great when I tried them on, but the first time I wore them I had a blister on my heel within 30 minutes. (And I wasn't even in the water! Just walking around the house.) I went online and bought this product that night. Let me tell you, the next time I wore those water shoes with this product...NO blisters, AT ALL. Not even a sore spot!! I am in awe. I've now tried this product with several other shoes that used to rub me as well, and same thing! This is my new best friend. Thank you, SportShield!" —Matthew Leonard
Get it from Amazon for $13.99.