Product details of Huntkey Power Strip SZN507 3M 4-Sockets Surge Protector One piece copper bar structural design. Safety shuttles help to protect user and their children. Silver-nickel contact switch to ensure the service life of the switch over 10，000 times. Copper plate inside in High conductivity. Environmental protection and fire retardant materials. With smart USB port for charging (Output : 5V/2.1A)， suitable for smartphones， Pad， MP3/MP4， digital cameras and other digital products. Why Copper?Copper is the standard by which electrical materials are rated and conductivity ratings are expressed as a relative measurement to copper. Except Silver， copper has the highest conductivity according to International Annealed Copper Standard (IACS). Warning :DO NOT overload This power strip is designed for indoor use only， put the power strip away from heat-emitting appliances such as radiators or heat registers. DO NOT put power strip in the wet surroundings. NEVER connect electrical devices， telephone， network or coaxial wiring with power strip during lightning and storming. DO NOT open power strip in any reason. Please keep children away from this products.