An electric blanket is a blanket that contains integrated electrical heating wires. Types include underblankets, overblankets, throws, and duvets. An electric "underblanket" is placed above the mattress and below the bottom bed sheet. This is the most common type in the UK and Commonwealth countries, where it is known by default as an "electric blanket"; in the U.S. and Canada, where it is less common, it is called an electric heated mattress pad. An electric "overblanket" is placed above the top bed sheet, and is the most common type in the U.S. and Canada, where it is called an "electric blanket".