Surge arresters are used to protect electronic appliances and machineries from damages caused due to sudden voltage surges. 

Because of the changing lifestyle of the working population and the increasing disposable income, automated electronic products are used more and more widely. For protecting these devices from voltage fluctuations, the demand of surge arresters becomes large. Furthermore, the growing awareness for need of renewable energy sources is also acting as a driver for the market. Using renewable sources of energy such as sun, water and wind, this factor is creating the need for surge arresters in order to protect the heavy machineries from damages caused due to voltage overflow and fluctuations. 

Kingtronics sell 2-Electrode arresters and 3-Electrode arresters. Surge arresters operate on the gas-physical principle of the highly effective arc discharge. Electrically, surge arresters act as voltage-dependent switches.
More details about Kt Kingtronics Surge Arresters, please see:
http://www.kingtronics.com/surge-arresters