The D&Z-Vibe's new dynamic design allows the therapist to use it as the Z Vibe or the Double Z Vibe simply by unscrewing the improved switch at the other end and attaching another tip. The tip is sealed off from the internal components so no saliva, water or moisture can enter from this end. The kit comes in our handy Carry Case that easily fits in a purse and a second tip, the Preefer Tip. The D & Z-Vibe requires a special battery that is not readily available in retail stores. You can purchase a spare from Southpaw (p/n 208039).