Right, I had bought Size 3 Tommee Tippee Closer To Nature teats a few weeks ago. I bought 3 packs of 2. I decided this afternoon that I would try O with them. He's been getting knackered on the bottle again which was 1 of the signs last time that I needed to move up. I was popping them in my steriliser when I realised that they had no vent in them. All my other teats are vented. I didn't buy them for that reason, they were just the bottles/teats that were bought for my baby shower & they worked for O so there was no reason to change. Now I realise that I've only gone & bought the teats that are meant for the anti-colic bottles. My question is, can I still use these non vented teats with O? My friend pointed out that there was no such thing as vented teats years ago & we had no problems but I'm confused now. Advice?