Cable glands are mechanical cable entry devices. They are used throughout a number of industries in conjunction with cable and wiring used in electrical instrumentation and automation systems. Cable glands may be used on all types of electrical power, control, instrumentation, data and telecommunications cables. They are used as a sealing and termination device to ensure that the characteristics of the enclosure which the cable enters can be maintained adequately. Cable glands are made of various plastics, steel, brass or aluminium. Waterproof cable gland intended to resist dripping water or water pressure will include synthetic rubber or other types of elastomer seals. Certain types of cable glands may also serve to prevent the entry of flammable gas into equipment enclosures, for electrical equipment in hazardous areas.