Ultra-Sil Stuff Sack Set

The Sea to Summit Ultra-Sil Stuff Sack Set is three drawcord stuff sacks made from 30D Ultra-Sil nylon, a silicone-treated fabric woven with CORDURA yarns. Buy it as a 3, 5 and 8 L set or a 5, 8 and 13 L set, and turn a pack full of loose gear into a few colour-coded bundles you can find by feel.

What it keeps dry, and how dry

These are organisers for the inside of your pack, suitcase or bike bag. The fabric sheds light rain and splashes, with a PU coating inside rated to 2000 mm hydrostatic head and a DWR finish outside, which keeps a damp tent fly packed alongside off your clothes and sleeping gear.

They close with a drawcord, not a roll-top, and the seams are stitched rather than taped, so they are water-resistant rather than waterproof. For anything that has to survive a river crossing or ride on a kayak deck, pack it in a roll-top dry bag and keep these for sorting.

Capacity and what fits

• 3/5/8 L set, 76 g: a 3 L for toiletries or chargers, a 5 L for a beanie, gloves and thermals, an 8 L for a day's spare clothes. Right for travel, day packs and carry-on bags.
• 5/8/13 L set, 100 g: steps up to a 13 L sack that takes a puffy jacket or the clothes for a multi-day walk. Right for overnight and multi-day packs.

Each set comes in three colours, so the kitchen, the clothes and the sleep kit are easy to tell apart in a dim tent.

Material and durability

Ultra-Sil is 30 denier nylon made with CORDURA yarns, bluesign approved, with a non-PFAS water repellent finish. The stress points are double-stitched and reinforced, and the drawcord throat is built to stand up to hauling a full sack shut.

Packing and carrying

The slippery fabric slides into the gaps of a full pack, and a webbing grab handle on the base lets you pull a sack back out without unloading everything on top of it. Hypalon pull-tabs on the drawcord and the throat make the sack quick to open and close, and the Capture Cord Lock holds it shut.