The Sawyer point one has a gravity hanging kit that can attach to the bottom of a 5 gallon bucket...or larger. Best part is you can use it this way, or take it off and take it with you on the go in your BOB. I have it for my SAR Gear and it works great. But DO NOT let it freeze; it will ruin the filters effectiveness. Although it will look fine, it will not work to remove bacteria after it was frozen.