Instruct: Classify a given Amazon review as either positive or negative.
Query: Not worth the effort if you breastfeed

I bought one of the 4 oz bottles to try for my breast milk so my husband could feed our son. Our son had gas and spit up alot and we found the Avent bottles the best for him along with gas drops. My biggest complaint is how the screw cap attaches to the bottle as when you shake the bottle without the inside parts- the inner cap moves and milk goes everywhere. Maybe not a problem if you make formula and use right away with parts in place but when you put your breast milk in it for future use, I did not want to put all the parts together as breast milk separates. I also found it too long to clean and think that the idea is good but needs a bit more improvement.