The high quality laminated construction of our probes means the electrodes are built in to the main body of the probe. This means the conductive surfaces will never become detached or wear out! You can also use this Electrastim Midi Electro Butt Plug as a uni-polar probe by just connecting one cable instead of two. Stimulation will only be felt on one side but by adding a smear of conductive gel across the base will effectively create a fairly good uni-polar probe. You will need an electrastim erotic electro stimulator to use this item. Size: 70mm insertable length x 40mm diameter (2.75" x 1.6")