1. Safe BPA-Free Glass (4-Pack, 12oz)​ Each 12oz cup in the 4-pack is made of non-toxic, BPA-free glass—safe for daily use. It won’t absorb odors/flavors, keeping milk, juice, or smoothies pure for toddlers. 2. Dual-Lid Versatility (Sippy Cup + Mason Jar)​ Each cup includes 2 lids: a straw lid (for independent sipping) and a tight screw-on lid (for use as a Mason jar/snack container). Perfect for drinks (straw lid) or storing snacks/leftovers (screw-on lid). 3. Leak-Resistant Straw Design​ The straw lid has a soft food-grade silicone straw and leak-resistant valve—prevents spills during normal use (note: minimal leakage may occur with excessive shaking). 4. Easy Clean (Detachable & Dishwasher-Safe)​ All parts (glass, silicone sleeve, straw, 2 lids) are detachable. Smooth glass resists residue; top-rack dishwasher-safe. Hand-wash lid valve for best leak performance. 5：Gentle Reminders for Safety To keep your little one safe and your cup in top condition: ① Never put the lid in the microwave—it’s not heat-safe! ② If the cup has been in the freezer, give it a little time to warm up before heating to avoid any glass surprises. ③ For freshly made hot drinks, let them have a quick cool-down break before sealing with the straw lid. Safe sipping starts with these simple steps!​ Sursip Toddler Glass Sippy Cups, Kids Baby 12 oz Spill-Proof Water Tumbler with Straw and Lids, Smoothie Snack Mason Jar For Travel School or At Home, 4 Packs