Book style opening on main compartment; Can be worn 2 different ways; Ergonomic. internal frame offers increased balance and support; Meets most airline carry-on standards; Adjustable. padded hip belt for stability and weight distribution; Straps can be tucked away when not in use; External attachment points for items such as jackets. yoga mats. or sleeping bags; External Compression straps; Fits a 15 inch MacBook; Internal compression feature to keep gear in place; Sternum strap; Internal pockets to keep your gear organized; Internal attachment point for wallets and keys; Pen loop; Water bottle pocket