The CC9092MD(MG9092D) magnetic dallas key reader for iButton with steel rings is a unique device that was designed to hold a magnetic fob in place by means of magnetic force. The housing is built from a non-magnetic metal, which has a round, flat face in the front and – in the middle of this face – an insulated, spring-loaded pin (which acts as the contact). Built into the magnetic probe are small magnets which create the required magnetic field. This attracts magnetic metals, and thus pulls and holds them onto the front face. At the back of the probe is a solder lug (for the ground signal).