a backpack that has a water pouch in it and a tube so people can remain hydrated while trekking
                                                            
                                                     
                        
                                                
                        
                        
                            a portable water storage system in a handy, compact backpack
                                                            
                                                     
                        
                                                
                        
                        
                            ( noun) A backpack manufactured by CamelBak Products, Inc. containing a water bladder and a hose.