Shoulder straps are made to allow airflow through; System for hydration pack; External attachment points for items such as jackets. yoga mats. or sleeping bags; Fits a 11 inch MacBook; Hidden pocket; Adjustable. removable hip belt for stability; Attachment points on shoulder straps for small items such as pouches or water bottles; Sternum strap; Internal pockets to keep your gear organized; Internal attachment point for wallets and keys; Pen loop; Water bottle pocket