Conduction is the movement of heat resulting from direct contact with a surface. For example, footwear in direct contact with a hot or cold surface will warm or cool the feet faster than if it is in contact with hot or cold air. Wet clothing transmits outer temperatures to the skin faster than dry clothing. Protection from conduction, such as wearing a waterproof or water-resistant outer shell in inclement weather, is important to maintain warmth. Some materials such as metals are great conductors, while materials that are very poor conductors are insulators.