Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Not worth the money.

I chose this bottle system for my son after reading so many great reviews, and even bought one and ran it through the dishwasher to test for leaks...no leaks...They worked well, UNTIL recently. My son is 4 months old and they all LEAK. Constantly. I fill one up to put it in the diaper bag and within a half hour it's empty. They aren't very durable, the plastic on the rings is actually breaking off and now I'm going through the struggle of trying to find a new bottle system that my son will take (I hate the liners)...And they never did reduce the amount of air in the bottle at all. Do not buy these bottles unless you want to buy a completely new system in 4 months.