LIGHT-WEIGHT, EASY TO USE, FILL AND CLEAN - Easy to fill the bladder with lots of pocket space for storage and plenty of room for water, includes straps that are comfortable to wear on your back PERFECT SIZE FOR DAY HIKES & MOUNTAIN BIKING - Includes a safety whistle built into the buckle for use in emergencies, and reflective trims that increase your visibility at night CHOOSE A BLADDER SIZE TO STORE 3L / 2L / 1.5L of water in your day pack - the hydration pack backpack has a heat-sealed water bladder bag to prevent leaks and adjustable shoulder straps A PERFECT GIFT FOR YOUR HUSBAND, WIFE OR KIDS - This well made comfortable pack works great and uses good quality materials making it a great value that will make your loved ones very happy & safe while using it BACKED BY ADURO SPORT LIFETIME 100% SATISFACTION PLEDGE - If you ever have any issues with this product, simply let us know and we'll resolve it quickly " Aduro Sport Hydration Backpack [Hydro-Pro] 1.5L 2L 3L BPA Free Water Bladder Unisex Water Resistant Durable Light Weight Adjustable Sizing - BLH9ERDA5