1. SAFE MATERIAL & DURABLE: The kids mugs are made of 304 stainless steel, BPA free, they are safe for both kids and adults to drink cold juices or hot chocolate. Unlike glass drinking glasses, they are not easy to break, and they will not rust with long-term use, and are healthier than plastic mugs. 2. EASY TO HOLD: Each stainless steel mug comes with a silicone sleeve for non-slip grip & heat insulation. The sleeves are upgraded to full wrap which can be used multiple times as coasters to protect hands from hot or ice cold drinks. It not only makes the mug easy to hold, but also protects your furniture from stains. And the sleeves come in different colors which allow your kids or friends to identify their own mugs. 3. LEAK-PROOF LID & METAL STRAW: When the lid of our unbreakable water bottle is closed, they are completely leak-proof, no more worries about your child spilling the drink everywhere. And there are bendable stainless steel straws for your convenience. You can choose to drink directly from the rim of the mug or insert the straw into the central hole of the lid to drink with a straw. 4. MULTI-USE: The metal mugs can be used for water, milk, juice and coffee on the go, both for kids and adults, hot and cold. And the mugs can be easily taken anywhere, such as outdoors, camping, parties, beach, wine, pints, snacks, barbecue, picnic and any other activities you may have in your life. 5. EASY TO CLEAN & SPACE-SAVING: Our drinking mugs are dishwasher safe and stackable, which is convenient to store without taking up much space.