Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Doesn't really work

I bought this for my 10 gallon hedgehog's cage.The directions says that it's better to put it on a side, to avoid contact with water that could produce an electroshock.Well, I did that and only the part where it was got warm. The rest of the cage was still cold.I waited for six hours and nothing happened.So I decided to put it under the cage, under my hedgehog's sleeping place.At least it warmed that small zone.It's been like 8 months since I purchased it, and yesterday it stopped working.Wasn't worth my 20 bucks(that's the price at Pet Smart).