What does the number on them mean? all of mine have a number one on them, DS has the odd bottle of EBM, lately he struggles and am wondering if flow is too slow? He is 3.5 months, and have been using same teats since birth, should he now be on the medium teats? And is the number one teat the slow teat? would just pop to tesco to have a look at their teats but got so much to do today....
TIA