The Rhumkorff's Coil (or Spark Coil) has been used in Australian schools for many years. The vibrating points are tungsten and a high quality capacitor is used to reduce arcing. A fuse is fitted to protect the primary winding. The secondary winding, containing thousands of turns, can be slid from the primary to reduce the coupling. The unit runs from about 6 to 9V.DC. and a spark length of about 25-30mm long is normal. It is complete with removable and adjustable needle points with insulated handles. Should be used only with supervision.