newborn and full-term sizes, but after speaking with the company's customer service department these are the same size (0 to 6 months and come in original or vanilla scent). I also learned that the hospitals are the only ones authorized to get the smaller size (color green) for preemies and poor suckers. In addition, the pacifier is only recommended to be used up until 6 months as a baby with teeth may be able to bit off parts of the pacifier.
Per the product description, they are distributed to hospitals nationwide, constructed with durable, latex-free silicone and shaped to baby's face while staying clear of the nose.
I've used it for my newborn to soothe her when she just wants to suck and so far good results. Introducing a pacifier at 3 weeks has not interfered with her breastfeeding latch, which was my fear, and allows her to suck on something besides my breast or finger when she just wants to suck.