E-Stim small beaded urethral bipolar plug soundthis E-Stim sound is a beaded bipolar soundsimply plug it into your power box, and either insert past the black divider at approximatly 4-1/4" inches or grasp the metal on the shaft before the divider ring to complete the circuit and feel the electricityflexable shaft with beads give a unique sensation 3/16" x 5" insertable fits most power boxes power box not included