Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Does not work properly

I am not sure why I did not trust the negative reviews of this product; I suppose as there were some counter balancing positive reviews, or possibly some people did not know how to properly operate it. So I decided to give it a try. Wrong! A total piece of C---. To set off the sensor requires a Mac Truck in front of it. The sound once activated did scare off the cat. But it required me waving my hand in front of the unit to finally make the sensor to activate. Returned the unit the same day it arrived. Thanks to Amazon for making returns easy. Onward to another unit.