This is a dedicated insulated case L size for HIKEMAN hydration packs. I am selling this because the hydration pack broke soon after I purchased it. ■ Description: Condensation Prevention: This cover was created based on customer experiences of "the contents of the backpack always get wet from condensation when a hydration pack with cold water is placed directly inside." It allows you to easily carry your hydration pack without interfering with the other items in your backpack. Usable in all seasons: Made with PEVA material, which is strong for cold retention, you can drink cool water from your hydration pack even in the summer when you put ice in it. The cushioning material inside also has excellent insulation, and when placed in a backpack, it can also be used as a dedicated insulated case to prevent freezing in the winter. PEVA inner material: The inner material of commercially available hydration pack insulated cases often uses aluminum, which deteriorates easily. In comparison, this dedicated insulated case uses durable PEVA, which does not peel off even after years of use, allowing for longer use. Comprehensive protection for the water supply pack: This hydration cover has thick cushioning material throughout. Even if you accidentally bump into something hard when you're tired, you can still hydrate without easily breaking your precious hydration pack. Detailed design: This is a dedicated protective case that can be adapted to over 90% of commercially available hydration packs. It features handle designs on both sides of the bag for securing the tube, and a smooth-opening double zipper at the bottom for easy attachment and detachment of the tube. It's a great item for mountain climbing and other activities.