E-Stim Hollow Butt Plug by Zeus Electrosex. The plug is made of silicone and can be used with a Zeus powerbox. The wavy design provides extra stimulation and the inside of the plug is hollow. This creates an opening for fingers, lubricant, sex toys etc. Warning Do not use in case of heart complaints/pacemaker or with cardiac arrhythmias Do not use if you are pregnant Do not place on eyelids Do not place on damaged skin  Avoid abrupt changes in shock in/adjustment  Keep out of reach of children Do not turn on the control unit until you have attached the accessories to the body, not before.