These are low sensitivity, directional vibration-induced trigger switches. Inside is a very soft spring coiled around a long metal pin. When the switch is bumped from the side only, the spring attached to the first pin touches the center pole to make contact with the second pin.
So when there's a bump, the two pins will act like a closed switch. When everything is still, the switch is open.
Product Dimensions: 18.0 x 15.8 x 5.5mm
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