Features:

• Cat deterrent safely and effectively repels unwanted cats
• 2-second ultrasonic alarm when motion detector senses motion
• Not audible to humans; covers 330 square feet; requires 9-volt battery
• Weatherproof and can be left outdoors in all conditions
• Measures approximately 8 by 3 by 18 inches

Editor Reviews:

Product Description:
- Automatic outdoor cat deterrent. - Easily and safely keeps cats out of your garden and flower beds. - Motion sensor activates a loud, 3 second ultrasonic sound that scares cats away but humans can't hear. - Requires one 9-volt alkaline battery, not included. - 2 year warranty.

Rating : - Contech CatStop Cat Deterrent has no effect on cats
I tried the Contech CAT001 CatStop Ultrasonic Outdoor Cat Deterrent in my backyard for over a month. Cats walk directly in front of it, it detects them but has no effect on them at all.