Leak-proof Straw Cup: 3 levels sealing structure, seal lid buckle + seal straw buckle + internal V-shaped lock, no leakage when inverted/shaken. It is more convenient for babies to drink water independently. Scientific Drinking Water Manager: High-definition transparent visual window, with capacity marking lines. It can easily track the baby's daily water intake and drink water more regularly. Upgraded Spill-proof Straw: Seposeve's unique V-shaped structure is used inside the straw sippy, and water will only come out when the baby bites. Effectively prevent dripping, and at the same time have the function of controlling the water flow rate to prevent choking. Ultimate Grip Experience: Ergonomic wave pattern double handle design, non-slip and labor-saving, optimized for baby's cute little hands, easy to drink water even with one hand. High Quality Safe Material: Made of food grade silicone, soft and elastic. No odd smell, no potential small parts. Dishwasher & freezer safe. CPSC certified laboratory tested, more assured for infants and toddler to use. Clean with boiling water or steam before first use. Drinking cup and leak-proof straw are detachable, rinse with clean water before/after use. Scientific Drinking Water Manager: High-definition transparent visual window, with 2 capacity marking lines. It can easily track the baby's daily water intake and drink water more regularly.