Instruct: Classify Amazon reviews into positive or negative sentiment
Query: good for very short time

The batteries don't last very long and are expensive to keep replacing and the collar itself stopped working all the time after about 6 months. It will work sporadically but I need it at all times for my cocker that just doesn't get that he isn't suppose to bark all day long and at everything! Very disappointed in them as I bought two for both dogs and now I am out that money and have to look for a different kind that WILL work!