Dallas iButton magnetic key used for personal identification.
This device is indestructible, unalterable, can not be copied, can not be intercepted.
The magnetic key is particularly useful in situations where it is necessary to maintain an active command for all the time in which the key is detected on the reader. In this way you can create a safety switch that can be operated only by who has a key enabled.
The key model is the DS1990 read-only.
The key reader is sold separately.