I had problems with this unit from the outset as it flattened batteries very quickly. It is supposed to be heat sensitive as a Passive Infrared Detector (PIR) is allegedly used which should detect body heat and trigger the device. It should therefore react only to animals and birds. However we found that it detects any movement whatsoever - e.g. falling leaves, wind movement of plants, any movement at all of anything with or without body heat. When I raised the issue that the unit is not as labelled by the supplier and had cost me 2 sets of 9 v batteries in a few days, Aussie Gardener was great in trying to obtain resolution from the supplier. After several attempts to get resolution over a period of about a month the supplier finally admitted that the unit reacts to all movement (so does it actually have a PIR detector?) and to use a power adapter connected to 240 v power instead of batteries. This is not an option as we want to use it outdoors and as labelled. Aussie Gardener discovered from their own testing the truth of our claim and offered us a full refund. However when we learned it would have been at their cost without recovery from the supplier we decided not to do that to these good people. So we've decided instead to write this frank review and I have done the same on Product Review. On the positive side the unit does seem to be effective in deterring animals. But a big thank you to Aussie Gardener for trying to resolve this - we will stay with you as customers because you do treat your customers the way we want to be treated. That is important.