The Tulsa is an 18 litre foldable backpack that can increase to 28 litres when unfolded. It has a main compartment with double zippered closure and an easy access due to its top zipper, plus a padded 16" laptop compartment with side zippered closure. Backpack/Capacity: 18-28 Litres. You can increase 10 litres when backpack is unfolded/Dimensions: Fold 48x32x14cm, Unfold 67x32x14cm/Main compartment with double zippered closure and an easy access due to top zipper/Independent padded 16" laptop compartment with side zippered closure/Ergonomic shoulder straps