I spent two nights reading everything I could find.

I wasn't looking for something to kill the roaches that were already there.

I was looking for something that could make my unit specifically a place they wouldn't want to be regardless of what was happening anywhere else in the building.

That's when I read about how roaches actually choose where to live.

Most people think roaches go where there's food and warmth. That's partly true.

But roaches also read their environment acoustically. Their antennae are tuned to the vibrations and sound frequencies around them. Those signals tell them: is this space safe? Is this a good place to feed and nest?

When the acoustic environment of a space is disrupted when it feels wrong at a sensory level the roach's own nervous system tells it to leave.

Not because something killed it. Not because a spray touched it. Because the space itself became uninhabitable to its biology.

And here's what makes this different from everything else: roaches cannot build resistance to this. They can evolve resistance to chemical compounds. They cannot evolve away from their own nervous system's response to environmental signals. That's a fixed feature of their biology and it's been fixed for 300 million years.

I'd seen cheap ultrasonic devices before. The kind you see at the dollar store.

I'd dismissed them and I was right to. Those cheap devices emit a single fixed tone. Roaches detect it once, then habituate like a sound you stop hearing after it plays long enough.

Real ultrasonic protection has to vary its frequencies continuously. That's what prevents habituation. And it has to be engineered specifically for the size and sensitivity of a cockroach's sensory system not a generic device that costs $9 and claims to repel everything.

That's when I found PestLab.