Instruct: Classify Amazon reviews into positive or negative sentiment
Query: no good for high pitch yipping

I have a Tibetan Terrier who ONLY barks when left alone for long periods of time. So it was very difficult to test this product, since he won't bark when we try to make him. Still, we'd put it on and leave and the neighbors would complain when we got back. I finally called the company and the customer service rep asked if the dog has a high pitched bark. The dog has a VERY high pitched bark. Turns out, their older models (which they no longer sell) work fine with a high pitched bark, but the new model (the one with the on/off switch) doesn't work at all with a high pitched bark. They offered to change out our model for the older version, which I guess they keep in their warehouse for this very purpose. But, if your dog has high pitched bark, you're better off calling Premier directly and figuring out how to get the older model. Or find a brand that works.