This Knobber massage tool is a simple device designed to let you apply deep pressure to muscles within easy reach of your hand. It the ideal instrument for clinic or home use allowing for firm, sustained pressure on targeted muscle. It is as safe and effective as massaging a sore muscle with your own knuckle or thumb. It's unique patented design allows it to be used in several hand positions and by the right or left hands comfortably and interchangeably.