Magnetic reed switches are devices consisting of a pair of ferromagnetic flexible metal reed contacts in a hermetically sealed glass, magneshere, or other molded body and are operated by an applied magnetic field. The contacts are normally open, closing when a magnetic field is present, or closed and open when a magnetic field is applied. The switch may be actuated by an electromagnetic coil or permanent magnet placed near the switch. When the magnetic field is removed, the reeds?return to their original position. Contact forms include SPDT and SPST.