This switch cuts off the fuel pump ground if the switch senses an impact. The switch is reset by pressing the top of the switch.
Good way to turn off the fuel supply in the event of a crash or impact. Not an overly sensitive switch.

Jim, tell us more about this. Are there stats on roll over, impact etc. Interesting. Mark

Don’t know about that…

Not sure about this particular switch since I don't know what vehicle it was designed for, but During my years I worked as a traffic accident investigator, I found these switches to be a valuable asset in stopping post crash fuel flow. Some were designed to cut off when sensing an impact of about 10 MPH and above and in a rollover the forces are such that it almost always will trip the switch.

The good thing is if the car has suffered an impact, but is still drivable, and the switch has been tripped, you simply hit the reset button and you're able to drive on. A good safety feature in most cases.

You have a PM.

I installed one that I got from Napa. It’s easy to test by giving it a smack with a dead blow hammer when the car is running.

Put one in my car. Very happy I did.

Ben, what model did you use. Mark

The one from Pegasus racing.