Designed with ultralight backpacking in mind the Ultra-Sil? Nano? Dry Sack is made from lightweight 15D siliconized Nylon. With the use of featherweight 15D fabric, these are perfect for use inside your pack to keep gear organized and dry. Using a hypalon roll-top closure that doesnt wick moisture, an oval base for easy packing, these are fully seam sealed for water resistance. Ideal for backpacking, climbing, cycle touring and modular packing where lightweight and low bulk is key.