Sea to Summit Ultra-Sil Nano Dry Sack

The Sea to Summit Ultra-Sil Nano Dry Sack is a family of ultralight stuff sacks made from 15D siliconised nylon, with individual sizes weighing 13 to 46 g depending on capacity. That fabric weight puts the range firmly in ultralight territory, for hikers organizing a pack's contents, clothing, electronics, food, without adding meaningful bulk. Waterproofing comes from a roll-top closure sealed with a Hypalon strip, rated to a 1200 mm hydrostatic head, enough to shrug off splashback, rain inside a pack, or a brief dunking, though not the same as a fully submersible dry bag for river crossings or paddling. The thin nylon is best handled with care around sharp gear like trekking pole tips or knife edges. Available in multiple colors and sizes, the sack suits a color-coded packing system for thru-hiking or bikepacking, keeping dry clothing, electronics, and damp items separated. It is a component piece rather than a standalone system, typically bought in multiples for different gear categories.