Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Would not recomend this product!

I was really excited to use these "venting" bottles. I have twins, so made sure we stocked up. After about two feedings we realized that they leak!! Also, the markings on the side wear off easily, so make sure you don't scrub the outside. I would highly recomend using the Drop-In system for several reasons 1)Less washing (only have to wash the ring and nipple..I only rinse the bottle since no formula actually touches it) and 2)It works like it says...no air