It's not much to look at. It's round. A sort of dull translucent grey (though I've been told that they also come in a variety of exotic colours).
It's also sort of rubbery. The blurb on the cover says 'Resilient'. That's about it. Can't think of anything more to say to describe its simplicity of design any better. Its usage is as simple as its design. In times of extreme emotional stress (which, in my case, happens approximately once every 15 minutes or so), all I do is hold it in my hand and go squeeze, release, squeeze, release ... you get the picture. In some magical way, all the tension and stress drain out, leaving me fresh and eager to face the next challenge. (OK, that's a bit of an exaggeration.)
After a bit of thought, I've figured out that it works on the same principle as taking out one's frustrations on a punching bag. Difference is that it's a lot more convenient. To complete this article, a quick look at another product that aims to fulfill a similar purpose: the Chinese health balls. Similar round design, but there the resemblance ends ... they're far more stressful to use - as anyone who has ever tried to simultaneously rotate those two balls will tell you!
So if you're looking for a stress-reliever option that reduces both form and functionality to its basics - they don't come much simpler than the stress ball!