[MrsS]

I loved the gussets on the Duos and actually used my size two duos on my 9 and 10lber just fine. They were puffy but they didn't gap or leak. So if you have big faster growing babies you can go straight to size two. The flips don't have gussets and didn't fit as tight around the thighs. I didn't use them much at all till he was 9months.