Fangrui Product Details Leak-proof : Experience The Convenience Of Spill-proof Caps, Transforming Standard Water Bottles Into Sippy Cups That Release Liquid Only When Sucked On. Say Goodbye To Travel Spills And Hello To Peace Of Mind. Universal Compatibility: To Fit A Variety Of Standard Size Bottles, Including Water, Soda, And Even Beer Bottles, Caps Are Dentist Recommended And For Everyone From Babies To Adults. Use Them With Reusable Straws For An Eco-friendly Option. Safe And Design: These Caps Are Safe For All Users. Theyre Enough To Withstand The Bites Of Teething Babies And Can Even As A Soothing Teething Toy, While Also Helping Babies Learn To Transition From Bottles To Cups. Portable And Easy To Clean: Caps Are And Compact, Fitting Easily Into Any Diaper Bag Or Pocket. Theyre A Hassle-free Alternative To Bulky Sippy Cups, Built To Last Through All Your Travels And Adventures. Simple Operation And Maintenance: Using Is A Breeze-just Push The Cap Onto The Bottle For A Tight Seal And Open The Top. Cleaning Is Equa