The main difference is that combination seats are only forward - facing and come with extra booster settings. (mommystroller.com)
You can forget about buying extra boosters or separate overnight diapers with the O.N.E.. We've included a handy dandy snap - in booster that can be used for heavy wetters or as an overnight night solution. (diaperjunction.com)
You do n`t need extra boosters or add - ons with Rockin» Green. (teenygreenykc.com)