Thinkbaby products address the growing concern of toxic chemicals leaching from consumer products. All products are free of bisphenol A (BPA), lead, PVC, phthalates, melamine, nitrosamines, and biologically toxic chemicals. The Slow Flow Cross Cut nipples feature our anti colic system, which helps reduce gas and spit up. The anti colic system is actually built into the nipple for easy cleaning with no little parts to lose or break. The Slow Flow Cross Cut nipples are designed for newborns to 3 months. If your child is between 3 and 6 months, we recommend our Medium Flow Cross Cut. For ages 6 to 12 months, we recommend our Fast Flow Cross Cut nipples. The advantage to the cross cut design is that is no spill. For extra strong feeders, we do also offer Single Hole nipples. The nipples are dishwasher safe (top rack recommended). One of the great cost saving advantages of the Thinkbaby line is that you can extend the life of the baby bottle by simply purchasing the Conversion kit. The Conversion kit transforms the baby bottle into our award winning Sippy cup. For parents this means, no more throwing away baby bottles after one year and for the environment no excess waste. Most little ones become ready for the transition between 9 and 12 months. Check out our top selling Complete BPA Free Feeding Set. Thinkbaby's products are recommended by Healthy Child Healthy World.