Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Unreliable Product

I bought this product with a life-and-death importance. My rescue Great Dane is aggressive toward cats. I tried the collar on myself and turned the shock rating up to 5 before I got a little jolt. Then I tried it on my dog and calibrated according to the instructions. I presented the cat and got limited reaction even on the highest 10 setting. I tried the collar on myself on bare skin. I felt a shock about one in four times -- on my bare skin.This product is unreliable.