I'm a breastfeeding momma and was recommended to try nano bebe bottles. I absolutely love them and he does too! I got a whole kit with bottles, nipples, warmer, storage bags, and a pump converter. They work extremely well and warm quickly and easily in the bottle. The coolest thing about them is that they have the shape of a boob. They're rounded out and have an indention on the inside for easy warming. I haven't had any issues with gas and the bottles are super easy to clean. The only downsides are that you need to make sure the bottom of the bottle is put tightly together and the last bit of milk is hard to make it available for the baby.