Heat Proof Water Cup with Plastic Straw, Large Capacity Leak Proof Tumbler with Lid, Non-Slip Grip & Easy Carry Handle for Travel, Gym, and Outdoor Activities

The cup has this slight whistle sound when you drink from it, not sure if it's because it's new or if it's designed that way but my kids love it! i love it! i need it in more colors and i have to buy another one because I'm not sharing! make sure to get some cute stickers to go with it and decorate the bottle! and the lock on it is very well made too.