How the Green Shield pest repeller works
Inside the Green Shield box is a small collection of electronics. When you plug the box into the wall, the device starts automatically (there are no controls to learn, it's either on or it's off) and the electronics start emitting an electromagnetic field.
The field isn't static, though. It pulsates, cycling through different frequencies thousands of times per second. This is what makes the pests feel so unhappy. They don't like it. It's the sort of discomfort you'd feel in a room someone had told you was haunted - not something you can really put your finger on, just a feeling that you don't want to linger any longer than necessary.
The field is invisible and intangible to humans. You have no way of knowing it's there. That's why we put a little flashing light on the front of the Green Shield, so you know it's working.
You can picture the field in your mind's eye, though.
The field is bubble-shaped, with the Green Shield sitting at the centre of the bubble. Cone-shaped spikes also poke out from the bubble, along the lines of the electric circuit the machine is plugged in to. The cones get narrower - and the field weaker - the further away from the Green Shield you go.
The Green Shield emits the field for approximately three minutes, then stops for a minute, then repeats the cycle. This gives the Green Shield a little time to rest its circuits, and also makes the pests more uncomfortable. Just when they think everything's fine again, the field suddenly re-appears around them. They don't hang around for long.
Better than ultrasonic pest control
The field produced by Green Shield is electromagnetic, but it is not ultrasonic. Green Shield is a better way of controlling pests, and has been proven to work; ultrasonic gadgets that emit high-pitched sounds (too high for humans to hear, but audible to animals, including dogs and cats) have been tested just as rigorously but generally don't make any difference.