Instruct: Classify a given review into positive or negative sentiment.
Query: Doesn't work well

It really disappointed me to use this pump, had it in my backpack waiting for the right time to use it, and when it came, I was pumping for aprox. 7 minutes until my arms start to feel numb, only to get my MTB tire semi inflated.Great exterior design, but the the pump itself is not what it should.