Duct tape is legendary, for a reason. It's saved nearly as many lives as the Polio vaccine and it's easily operated without a medical license. You can use it to make temporary weather-resistant patches for your gear, shelter, clothes, and if nothing better is available, for playing House on your buddy's exponentially growing blister until he can hobble back to base camp. Fits in the Gear Aid Kit. 2 rolls included- 50 inches each.