Optical tech, yep. I have three here I've never hooked up. There's no microswitch on the bottom, just some wire terminals like you'd see on a P360 stick. They're labeled G, C, and +5, so you can't hardly screw up.
They don't have any bezel around the button head; the whole top is press-able, and appears to be the same diameter as a Happ button including bezel.
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