The only cat deterrent tested & approved by the RSPB!CATWatch, the UK's leading cat deterrent manufactured in the UK, has successfully completed a two-year scientific trial conducted by the RSPB to determine its deterrent effect on cats in residential gardens. The results are published in the Applied Animal Behaviour Science Journal after peer review. The research concluded that CATWatch reduces cat intrusions into gardens. The longer the unit is in place, the more effective it is.CATWatch is weather resistant, cost-effective & approved by the RSPB. It also comes with a two-year warranty. How does it work? Push the Catwatch ultrasonic cat deterrent into the ground, & when the sensor detects movement it emits a high-pitched sound disliked by most cats (but inaudible to humans). The frequency emitted is unique to cats hearing range, so the Catwatch won't bother other garden wildlife, such as hedgehogs. Some cats will see the device as a challenge initially, & it may take up to four weeks to put them off coming into your garden.