Invention of the Belarusian neurologist Robert Wartenberg (1887-1956) , to which most attribute the idea to use the hammer to test reflexes , which began to use this tool in order to observe the reaction of sensory and neurological then on the most various areas of the body . The tool consists of a small wheel diameter of about two centimeters , from the sharp points and minute , combined with a long handle about seventeen centimeters. The feeling that returns the sliding of the wheel Wartenberg on the skin , and in particular on erogenous zones and genitals , it can be that of a very slight pain combined with a pleasant stimulation not dissimilar to that of a light tickling . An interesting variant is sure to add to the aforementioned sensory effects of the passage of electric current at very low amperage , thus increasing significantly the stimulation of epidermal area treated. Normally the scroll wheel should not apply pressure of the hand holding it , but it happens that I use is made different from the one originally designed for simple stimulator of the skin, thus causing tiny perforations and close cutanee.Tutt ' today you can easily find in trade for a few tens of Euros , even though it is no longer used in the medical field for reasons of hygiene, in its simple origiraria aesthetic conception , that is made of hardened steel , or stylized forms for BDSM rather than with cute handles colorati.Simpaticamente is also called " wheel for ravioli " for the obvious similarity with the distant relative used in the kitchen.