ARK's Roller Tip features a cylindrical design with a built-in stainless steel ball. Simply twist the tip into your Z-Vibe, turn on the Z-Vibe (optional), then roll it over muscles, along tendons and nerves, and around trigger points and joints. The smooth vibration and cool touch of the stainless steel provide sensory input that can be both soothing and stress/pain-relieving. Roll it along the Ulnar nerve, across the facial muscles, around the TMJ muscles to relax tooth grinders, around the knuckles for individuals with arthritis, etc. Please note: this tip is for proprioceptive input and sensory stimulation outside of the mouth - this tip should NOT be used inside the mouth.