EIO Glass Sippy Cup can transform any 8oz canning jar into a sippy cup.  We LOVE this thing, how did it take so long for someone to design this? 

The EIO Kids Cup uses a BPA free, valve-free, screw-top cap, an 8oz. canning
jar and an easy-to-grip silicone sleeve that transforms a glass canning jar into a
spill-resistant, modern training cup.

Each cup is a 8 oz. canning jar wrapped in a colorful silicone sleeve designed to make the cup easy to grip and hard to break.  This sleeve is dishwasher safe and can be left on the cup for cleaning.  It can also be transferred to other jars.  The lid is compatible with most 8oz canning jars as well.  How's that for versatile?

The EIO Kids Cup teaches toddlers how to sip from a cup, a speech development milestone for toddlers.