You get a two pieces like in the picture
This is a latching reed switch normally open.
a lot of people get normally open and normally closed mixed up so i will give you an example of how it works.
You want to turn a small motor on so you wire up this switch to the motor and a battery, once its wired up the motor is off then you take a magnet and touch it to the reed switch and the motor will turn on and and stay on, even when you remove the magnet the motor will stay on. once you turn the power off the motor will turn off then you can reconnect the power the motor is still off.
watch the video here
https://www.youtube.com/watch?v=NivPSpFEbNc&feature=youtu.be
Latching Reed switch
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