Which Philips Avent original Natural teat suits my baby best?

Teats are available for 0m, 0m+, 1m+, 3m+ and 6m+. See the image below for an overview. These Philips Avent Natural teats can be used on the Natural Philips Avent feeding bottle and Philips Avent storage cup. 

• The Natural First Flow teat (with the number 0 on the teat) is recommended for newborns and preemies. This teat can be used from day 1 and when switching from breastfeeding to bottle-feeding. 
• The Newborn teat (with the number 1 on the teat) is recommended for babies aged 0+ months old who are breastfed and bottle-fed.
• The Slow Flow teat (with the number 2 on the teat) is recommended for babies aged 1+ months old that are breastfed and bottle-fed.
• The Medium Flow teat (with the number 3 on the teat) is recommended for babies aged 3+ months old.
• The Fast Flow teat (with the number 4 on the teat) is recommended for babies aged 6+ months old.
• The Variable Flow teat (with the I, II and III markings on the teat) is suitable for babies aged 3+ months old. This teat has a slot cut into it which provides an adjustable flow rate. The flow rate can be varied by turning the bottle to align the I, II or III markings on the teat with the baby's nose.

Once the consistency becomes too thick for these teats, we recommend you to use the Philips Avent Thick Feed teat.

• If you are breastfeeding, we suggest staying with the Natural First Flow teat because it is designed to match the flow rate of the mother.
• If your child becomes frustrated at meal times, you may see them suckling hard, then pulling away, crying and suckling hard again. When your baby is taking longer than 20 to 30 minutes to finish a bottle, this may be an indication that the flow is too slow. If this is the case, change to a teat with a higher flow rate.
• If your baby lets go of the teat, is spilling milk, is getting too much milk to swallow or if milk is dripping between your baby's lips and the teat, the flow rate might be too fast. Change to a teat with a lower flow rate.

You can also use the Natural teats with a screw ring in combination with the Classic/Classic+ feeding bottles.