Features: Expandable attachment pack adds 6L capacity with waterproofed blend, featuring a versatiles pocket and elastic meshes for organized outdoor gear storage. Multifunctional design integrates water resistant compartments, adjustable straps for 99% backpack compatibility, and secure top drawstring with lock to prevent item loss during adventures. Designed for hikers, campers, and outdoor enthusiasts needing extra storage solution without added bulk to their hiking backpacks or travel gear. Ideal for mountain treks, trail running, or daily commutes to securely carry water bottles, rain jackets, climbing tools, and electronics in various weather conditions. Stretchable meshes expansion and reinforced fabric ensures durability while maintaining flexibility, making it a must have outdoor gear organizers for adventure ready backpacks. Specifications: Color:Two Choices Dimension:24.5×38cm/9.65×14.96in Component:polyester Package Includes: 1pc Expandable Hiking Backpacks note: 1.Please allow 1-2cm errors due to manual measurement, making sure that you will not mind before order. 2.Due to the differences between different monitors, the picture may not reflect the actual color.