For your adventuring prodigies, there's the Nalgene Kids On The Fly 12 oz. Water Bottle! It features everything that made its grown-up version wildly popular (one-handed opening, leak-proof design, durability, odor resistance), but its 12-ounce size is more manageable for little hands and thirsts. It's carabiner-friendly, so hook it to their backpack or your daypack, and get out there!