Step 3 Straw Top 8 months and up - Designed for teething Perfect softness of straw fits baby's sensitive mouth, helping baby make the transition of drinking liquids on his own.   The MagMag cup is designed to 'grow' with your baby's changing drinking patterns. Simply change the top of the cup. Begin with Step 1 (Nipple), then follow with Step 2 (Spout) and finally, Step 3 (Straw). The MagMag cup promotes baby's most natural drinking habits. How To Assemble? Connect lower straw to upper straw. Then, place both parts with the gasket to the inner part of the adaptor and close tight.