These are plastic balls that are on a loop of elastic that you put on your chair to massage your back. I was not impressed with these and felt like they need some improvement. First of all I hate how they look. They are just plastic balls on elastic with a knot. Second of all I think they are too big. And third I think they should have little nubs on them so you get more of a massage feeling. Currently it is just pressure on different points to me.
I received this item for free or a discounted price in exchange for an honest unbiased review. This has not influenced my opinions on the product.