Hi. Sa pagkaka-alam ko wide neck to mimic breast and nipple esp for breastfeeding mom na magpapadede ng pump milk. Slim neck, standard bottle lang, According sa reasearch, kung newborn daw gagamit, slim neck mas maganda. Pero for me, in my experience, kahit anong bottle pagnakasanayan ng baby, dedeen niya parin yan. Nasta make sure na quality bottle yung bibilhin. Formula feed baby ko for 2-3 days, pero EBF ako until 6 months, slim neck Pur bottle gamit ko.