Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Best when there is no socket

I have to pump in the bathroom twice a day in the office, as all the conference rooms are with glass walls and doors. Since the bathroom has no socket for me to plug in, I am really glad that this pump can be used with 2 AA batteries. I have been using it for 3 months already, and thankfully, my baby is still exclusively breastfed.Though I find the pump is really noisy with the loud humming sound (so I guess my co-workers using the next cubicle will know what I am doing), and does not work as well by using batteries: with slightly weaker suction, and the power runs out really quickly, that's the best electric pump in the market that I can find. I would recommend it to my friends who want to express in the office with no private office room. Or if you plan to travel without the baby.