Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: Unreliable

I like the design because it is easy to carry and easy to use. Unfortunately, that is not what matters. I run on back roads where every so often dogs like to chase. I was bitten once and swore it wouldn't happen again. This dog was part of a pack of three (I never see the owners despite all the barking). The next time they came after me I was ready. When they were about 4 feet away I sprayed but the cloud didn't make it to them. I sprayed again and I think the wind caught the cloud because one dog looked surprised. Apparently not surprised enough because they came after me again the next day with the same results. The next time they came after me I tried to spray them but the device didn't work. I got home, opened it up, canister worked, but the mechanism that makes the canister spray was broken. A cheap little plastic part. So, if you think you are safe carrying this thing, think again.