Magnetic reed switches cover the majority of low power switching requirements. Reed switches have unique switching capabilities making them an ideal choice in more and more new applications. The overall glass length is only 4 mm long. These small sizes pave the way for unique new applications in RF switching, medical applications and many more. Hermetically sealed reed switches (glass to metal seal) are impervious to almost all environments. This opens up a vast number of applications where they are the only technology capable of meeting specific requirements where certain mechanical switches and semiconductor switches are environmentally limited. Many thousands of reed switch applications currently exist with many more added on a regular basis. Reed relays and reed sensors both use the reed switch as the heart of their switching mechanism.