Find the perfect fit for most parts of your shaft with this bumper pack of 5 electrarings cock rings from electrastim. each of the rings has a unipolar 2mm input that allows it to be connected to an electrastim stimulator (sold separately). not only are electrarings functional cock rings that can improve the virility, they're the ideal alternative to vibrating cock rings. when you switch on your stimulator the rings come to life, making your penis tingle and contract in a way that no other type of sex toy can. some men can even achieve a hands-free orgasm with no other stimulation required.because electrarings are external electrodes, you should lubricate them with electro-conductive gel before use.dimensionsincluded in the set are 5 cock rings with the following measurements:36mm (approximately 1.4 inches in diameter)38mm (approximately 1.5 inches in diameter)40mm (approximately 1.6 inches in diameter)42mm (approximately 1.7 inches in diameter)44mm (approximately 1.8 inches in diameter)materialsmade from a solid bar of aluminiumuni-polar designvarious sizes to fit different parts of the shaft2mm inputrequires an electrastim stimulator to operate