Nothing to complicated about water bottles. You need water and you need somthing to carry it in. But not all water bottles are created equal. Our Lewis N Clark Water bottles are designed with a slim profile to fit exterior backpack water bottle pockets. They also have a built in loop that easily attaches to your pack and a flip straw for easy sipping. They have wide mouths so you can fill them easily and add ice if necessary. And these water bottles are super light and strong stainless steel. So bring one along, attach it to your pack and stay hydrated!