Controlled sipping for little water-drinkers with a lock-top that makes it leak-proof and spill-proof. For our adventuring prodigies, there's the Nalgene Kids On-The-Fly Lock-Top water bottle. It features everything little water drinkers need: one-handed sipping, leak-proof top, durable and odor resistant. Plus its 12-ounce size is more manageable for little hands and thirsts. It is carabiner-friendly, too, so hook it to a backpack and get out there.