It is a portable, self contained device that vibrates. It has a longer handle so I find it easier to use by myself than the bigger “gun” type. I can reach over my shoulder or behind my back with it. It has adjustable speeds. My Wahl hand held ($30 at Amazon and Walmart) is electric but some of the gun type are rechargeable. The gun types are more powerful usually but this one seems to be enough to help me.