【Ultimate Breathability and Cooling】Featuring the Aerosyx airflow carrying system with a five-way ventilation system (perforated shoulder straps and mesh back panel), this hiking rucksack effectively dissipates heat build-up, keeping your back dry and cool during high-intensity day hikes 【Extremely Durable and Weather-Resistant Construction】Featuring a tear-resistant main fabric and a reinforced XPAC base panel, this rucksack can withstand rugged mountain trails and sudden showers, allowing you to enjoy your outdoor activities with complete peace of mind 【Ergonomic S-Curvix Shoulder Straps】Featuring an S-shaped S-Curvix shoulder strap design, pressure is evenly distributed across both shoulders and the back. Compared to traditional flat shoulder straps, this effectively reduces fatigue and enhances freedom of movement. Ideal for long-distance hikes 【Dual-Tube System Compatible with Hydration Bladders】Equipped with a separate dual-path connection system, it is compatible with most hydration bladders (sold separately), allowing you to stay hydrated on the go. A quick-release buckle securely holds the drinking tube in place, enabling a hands-free drinking experience whilst hiking 【Multifunctional Design】Features an oversized external storage pocket with a detachable external strap, whilst the side pockets and base are fitted with elasticated drawstrings. Multiple external attachment points allow for easy access and storage, keeping your gear organised and within easy reach ASIN B0GVD2ZQL6 Size 18L Color Khaki Pattern Solid Brand Name Naturehike Model Name Longwa Sport Type Hiking , Cycling , Trekking Strap Type Adjustable Unit Count 1 Count Style Number CNK2550XB015 Material Type Nylon Product Style Daypack Outer Material Nylon Storage Volume 18 Liters Backpack Design Daypack Backpack Number of Items 1 Lining Description Nylon Apparel Closure Type Zipper Age Range Description Adult Backpack Harness Type S-Curve Harness Water Resistance Level Water Resistant Item Dimensions D x W x H 17.7 D x 10.6 W x 5.9 H Product Care Instructions Hand Wash Only Apparel Fabric Weight Class Lightweight Recommended Uses For Product Sport Other Special Features of the Product Adjustable