The Bi-Polar General Purpose Clamp is made by ElectraStim and will provide you and your sub with hours of painful pleasure.
It requires a small amount of conductive gel to be applied to the contacts as you clamp it to your nipples or other body part of your choice.
It can be placed on the penis, scrotum, clitoris or anywhere as it is for general purpose not exclusively for the nipples.
As it is bi-polar, you don't have to combine it's use with other toys to complete the circuit.
It reaches an opening length of 45mm so it is heavy duty and can clamp onto the biggest parts of your body if you desire.
Plug the device into an ElectraStim system with a 2mm pin socket or any other compatible control unit (adaptors can be used if necessary).
The clamp is part of any BDSM palette and this one adds quite a thrill.