Copper is one of the most commonly used non-ferrous materials in the metallurgical industry, second only to aluminium. It is an excellent conductor of heat and electricity and is widely used for electrical wiring and heat exchangers. It has no magnetic properties, which is one of the reasons it is used in the field of instrumentation. It is mainly used for electrical conductors. Thin and highly resistant conductor wires are used both as external cables and for domestic electrical systems, in lamps and devices such as generators, relays, electromagnets and telecommunication instruments. Its properties mean that copper is commonly used for plumbing and sanitary installations, taps, nautical equipment, electrical engineering and electronics, tinsmithery, architecture, coins, crafts, giftware, transport, construction and many other sectors.