The motion sensor of the Laser Guard detects approaching intruders and emits bright flashes of light, green laser beams and optionally also scare noises. Even before the heron lands at the pond side, he takes flight and fish are save in the pond.

The action of the Laser Guard is very effective against herons by three methods:
Flashes of light at different frequencies makes the area unpleasantly restless.
Herons can see green light very well and moving laser beams are considered to be dangerous objects.
The noise of a heron in danger, barking dogs and the terrifying cry of a poisonous frog scares off herons finally.

Flashes of light and laser beams already cause much distress around the pond. That is why you can switch off the sound by turning the knob on top of the Laser Guard to mute. Because herons quickly get used to deter methods there is variation in the program.
Also other animals who want to approach the pond are scared off (like cats).
Colourful fish in a clear pond are an easy prey for herons. That is why they need protection in every season. In springtime, herons are searching for fish to feed their young. In summer, young herons have fledged and start to feed themselves on the waterside. In autumn, the food supply is limited for herons and pond fish are an easy prey. Fish are the main feed of the heron, but his long beak can also injure large specimens dangerously. After a successful attempt the heron will return until the pond is fished out completely.