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

We purchased this warmer to reheat breastmilk and ready to feed formula. The temperature was very inconsistent, sometimes too warm, sometimes barely warm at all. It also continues to heat even after the warmer shuts off. If you aren't there to immediately remove the bottle it overheats. Of all my many purchases for our first baby I was most dissapointed in this unit.