I bought this spiky massage ball from Amazon to help massage the sole of my feet. This supposedly helps with plantar fasciitis as well but I couldn't attest to its effectiveness for that. It is made with hard rubber that has very little "give" - great if that's what you're looking for. I used to own a much softer one that I bought from a random HK shop, which fell apart completely after one year. This one from Amazon is much more sturdy and I believe it will last for quite some time.
