The SMJ 4 socket extension lead Protects computers and sensitive electronic equipment from being damaged by electrical surges and spikes, making this extension ideal for the office and the home. Surge Protection Extension Leads protect valuables from voltage spikes. Voltage spikes occur when there is a sudden change in power consumption, which could be caused by lights going on or off, large electrical equipment being used and lightning strikes. Four individually switched sockets with child proof shutters to prevent electrocution 13 amp rated. Keyhole fixing for tidy wall mounting. Fitted with 0.75 metre lead for your convenience. You may also be interested in Greenbrook Powerbreakers for further surge protection. See them Here.