The probe has three contacts/cables instead of the usual two so as to allow different connection permutations You can stimulate between the top two domes the bottom two domes or the top and bottom domes by simply swapping the connections around The gold conductive electrodes are only mounted on one side of the shaft which gives a much more focused stimulation that you can point in any direction by simply rotating it Warning: Current must never flow through the heart. Do not use if you have a pacemaker are pregnant if you suffer from epilepsy or on any broken or inflamed skin. Size: 100mm(max. insertion) x 25mm OD x 12mm ID(4 x 1 x 0.5 ) This amazing new tri-polar probe can be used for a mind blowing variety of vaginal or anal stimulation. The probe has three contacts/cables instead of the usual two so as to allow different connection permutations. You can stimulate between the top two domes the bottom two domes or the top and bottom domes by simply swapping the connections around. The gold conductive electrodes are only mounted on one side of the shaft which gives a much more focused stimulation that you can point in any direction by simply rotating it. There are so many options with this excellent probe you will spend hours discovering its pleasures. Although this is a tri-polar electrode only two of the poles/connections are used at any one time. This item is also perfect for use as a unit-polar probe. Just connect to the tip electrode and you have the ideal internal wand to find those sensitive spots including the prostate. To do this you will need to use another external electrode such as a cock ring or loop. Lubricants are a natural up-sell to electro stim toys as they are needed to completed the circuit between the toy and skin and also help avoid skin irritation. Water based lubricants are recommended based on their high ability to conduct electricity. Silicone is a natural resistor and is not recommended. Please Note: This item requires a powerbox to function.