Reed switch: A glass-encased switch containing two thin, ferrous reeds. It is highly responsive to magnetic fields. Magnet: A permanent magnet mounted on the movable part of the door or window. Housing: A sturdy metal casing (often steel or aluminum) that protects the reed switch and provides durability and tamper resistance. Wiring: Two or more wires connect the contact to the security system. Some contacts may have additional wires for tamper monitoring.
