These have been the only bottle I have ever had to purchase. The angled bottle design makes it comfortable to feed my daughter in any position. The vent at the bottom ensures that my child doesn't gulp down air. We have never had problems with this. The bottle does come apart into 6 (cap, nipple, top piece, bottle, bottom piece, vent seal). The cap has a special niche for the nipple so it doesn't leak during transport. If you are placing this bottle in water to warm it up, you will need to ensure it is dried or wrapped as water does get into the cracks of the bottom piece and will drip out when you tip the bottle if not dried properly. It is very important to take every piece apart to ensure proper cleaning (having to bottom open up makes it easier to clean in my opinion). When putting back together make sure everything is screwed back tightly to avoid leakage. I love that this set includes two different sized bottle, and two different sized nipples. I am set from baby to toddler with no need to purchase more!

Love the bottle, effective but the only thing is that it had à lot of pieces to wash everytime

The wide nipple helps eliminate "nipple confusion" when switching from breastfeeding to bottle feeding. Ventaire system helps eliminate excess air from entering babies mouth while feeding. A favorite in our household!