A spike guard also known as a transient suppressor is a device, which shields electronic devices and computer appliances from transient voltage or surges in electrical power. Standard voltage for American households and office buildings is 120 volts. Anything exceeding this amount is transient and can cause considerable damage to electronic appliances that are plugged into an outlet. A surge protector directs the extra voltage towards the outlet's grounding wire and prevents it from flowing through the electronic appliance.The surge protectors usually have 6 or 4 sockets with individual switches. http://amplify.com/u/a16e3w