FIT PERFECTLY: pack size of 16.5 x 8 x 6.0 inch with adjustable shoulder chest waist straps, will fit chest size teenagers/kids with 27 inch up to adults (men and women) with 50 inch . The chest and waist straps make sure the pack does not bounce when you move. LIGHTWEIGHT & SPLASH RESISTANCE & DURABLE: Upgraded lightweight and Splash Resistance nylon with 2 Liter balder (in total 1.1 lb) to reduce your load and protect your belongs stay dry in light rain, and its double built-in waist straps improve its wear and tear resistance to ensure the pack’s life last longer. REPLACEABLE 2L BLADDER: Includes a 2 Liter/ 70z BPA bladder which keeps you hydrated. Its air flow system also keeps the water fairly cool. Includes screw cap for a adding small ice cubes for cooker drink for one day hiking, cycling, running or riding. SMALL FRONT POCKET: The pack designed for RACING especially with a SMALL FRONT PACKET, a bunch of keys and one or one two granola. LIGHT & COMPACT PERFOMANCE: Designed with cyclists, runners, and hikers，team outing in mind, the hydration pack are compact and aerodynamic, offering featherweight stability on your back with minimized wind drag. They ensure top-notch body performance, perfect for intense activities from marathon training to cycling adventures.