Tommee Tippee Explora Truly Spill Proof Straw Cup is intuitively designed for guaranteed easier drinking and more natural transitions, our Advance-Flo Technology ensures that our truly spill-proof straw Cup is truly spill-proof, leak proof and easy to drink from, easing the transition from mealtime drinking to on-the-go active drinking. Unlike other valve systems, our Active Sensor valve is designed by a physicist to be both so sensitive that liquid flows on demand, yet truly spill and leak proof which makes this the perfect Cup for kids as they learn to get up and go! BPA free 2pk 9oz insulated bottles.