This MEC Waist Pack was used once as my husband bought a couple and decided he wanted the smaller one. It measures 33cm long and approx. 9cm deep and 12 cm high. It has an internal pocket and is large enough to fit your water bottle while you are hiking. It can also be used to carry a phone, camera, food, light jacket and other hiking necessities so that your hands are free on your hike. It has a convenient adjustable waist strap.