Thin, tapered spout designed for little mouths. Lid fits all other Playtex Spill-Proof Cups. The Sparklin' Sipster Cup has been designed with a feeding specialist and a pediatrician to help your child develop good drinking skills as early as possible. The Spout: Thin and tapered so your child gets a good seal; Hard plastic - great as your baby's teeth come in. Plus, The Sparklin' Sipster fits in most car cup holders.