Ultra-Sil Dry Bag

The Sea to Summit Ultra-Sil Dry Bag is a lightweight roll-top dry bag, made from 30D Ultra-Sil CORDURA nylon with taped seams. It lives inside your pack, keeping the sleeping bag dry and the rest of your kit sorted by colour and size.

What it keeps dry, and how dry

The fabric is polyurethane-coated inside with a water-shedding finish outside, the seams are taped, and the hydrostatic head is 2000 mm. The roll-top has a non-wicking hypalon strip so moisture does not track along the fold. Inside a pack on a wet week on the South Coast Track, that is what keeps your down and your dry clothes dry when the pack itself is soaked through.

For a bag that rides on the outside of a kayak or a bike, we'd give you a Big River instead.

Capacity and what fits

• 3 L (30 g): phone, wallet, head torch, first aid kit.
• 5 L (32 g): a day's food, or gloves, beanie and spare socks.
• 8 L (39 g): a down jacket, or a set of camp clothes.
• 13 L (47 g): a compact down sleeping bag, or all your spare clothing.
• 20 L (58 g): a bulkier sleeping bag, or clothes for a long trip.
• 35 L (74 g): a pack liner for a small pack, or a winter bag and jacket together.

With the top rolled three times the bags stand from 20.7 cm tall in the 3 L to 56.5 cm in the 35 L.

Material and durability

30D Ultra-Sil nylon woven with CORDURA yarns, bluesign approved, with a PFC-free water-repellent finish. The fabric is translucent, so you can see which bag has the stove in it without opening three of them, and slippery, so a full bag slides into a tight pack instead of fighting you.

The buckle is a Field Repair Buckle: if it breaks, a new one goes on and the bag carries on.

Packing and carrying

The oval base packs flat against its neighbours and stops a full bag rolling away down the slope while you set up camp. Push the air out, roll the top three times and clip it.