Travel-friendly massage ball

It's such a pain when flights gets delayed. But once in a while it can be an opportunity in disguise. I was walking around the airport shops, bored, when suddenly I spotted one of these little reflexology balls. It's simply a ball with spikes, small enough to fit in the palm of your hand.

Unlike a lot of other massage props I've tried, this one is relatively hard and doesn't give way too much when you press on it. So the massage is effective, if you want it to be.

I liked it so much that I rushed back to get some more before my flight - another back-up for me and one for my mother.

Do you have any favourite massage products?