Made of water-resistant polyester fabric. Lightweight and firm enough. Design for kids 3+ years old as their own travel hiking backpack, also for adults who need a small pack Padded shoulder straps with a chest strap can offer comfortable support on the back, perfect for a day hiking, camping, going to the theme parks, visiting a zoo/museum, going on a road trip, or other outdoor adventures Multifunctional interior pocket, with plenty of space inside for holding a change of clothing, hat, water bottle, snacks, and any other stuff during the day's adventure Safety features: a toy whistle on the chest strap, a reflective strip in the front, and 2 small reflective strips on the shoulder straps Small size:15.0 inches x 9.0 inches x 5.0 inches. Capacity: 14L. Medium size:15.5 inches x 10.0 inches x 6.0 inches. Capacity: 18L. Fit little kids to pack more needs in adventure Perfect one-day hiking backpack pack for kids boys or girls, with plenty of room to store your kid's travel change of clothes, hat, water bottle, and some snacks. Perfect size for kids aged 7 to 12 years going out for a one-day trip, hiking, camping, going to theme parks, or other outdoor adventures.