Classic+ New Born Flow (0m+)- Recommended for babies 0-1 month old- Fits all Classic, Classic+, Anti Colic !#!amp!*! PES BottlesClassic+ Slow Flow (1m+)- Recommended for babies 1-3 months old- Fits all Classic, Classic+, Anti Colic !#!amp!*! PES BottlesClassic+ Medium Flow (3m+)- Recommended for babies 3-6 months old- Fits all Classic, Classic+, Anti Colic !#!amp!*! PES BottlesClassic+ Fast Flow (6m+)- Recommended for babies 6 months old and up- Fits all Classic, Classic+, Anti Colic !#!amp!*! PES BottlesClassic+ Variable Flow (3m+)- Recommended for babies 3 months old and up- Fits all Classic, Classic+, Anti Colic !#!amp!*! PES BottlesClassic+ Thick Feed Flow (6m+)- Recommended for babies 6 months old and up- Fits all Classic, Classic+, Anti Colic !#!amp!*! PES Bottles