Hello Pistachio,
People who use their hands a lot (computer users, bakers, florists, hair dressers, etc) can tend to have many many trigger points in their arms. That looks to be a quite nifty device for releasing them. As well, there are other alternatives from a ball on the wall to simple massage on the points with your knuckles. To get an idea of the anatomy and such, a great book on the topic is Clair Davies Trigger Point Therapy Workbook.