Magnetic reed switches are used in active implantable medical devices as a simple way of placing the device in a known operational mode when a programmer is not available. For example, placing a magnet on a pacemaker sets it to VVI mode with a manufacturer-specified set of parameters. In other devices (e.g. implantable cardioverter/defibrillators), placing a magnet on the IPG inhibits the delivery of high voltage defibrillation.
Although the reed switches that I use don’t come from Meder Electronics, I came across a very cool video that Meder produced regarding their manufacturing process. The following YouTube video shows their complete process from the sputtering of the magnetic contacts through the hermetic sealing and final testing: