Ultra-Sil Pack Cover

The Sea to Summit Ultra-Sil Pack Cover is a rain cover for your backpack made from 30D Ultra-Sil siliconised nylon, cut without seams so there are no stitch lines for water to find. It weighs between 57 g (XS) and 130 g (L) and packs into a stuff sack that stays attached to the cover, so it lives in the pack for every walk.

Who it's for

Walkers who want their gear dry at the end of the day without carrying much to get there. Pack fabric sheds a shower, but seams and zips let water through once the rain settles in, and a wet sleeping bag at the end of a day on the Overland Track or in the Victorian high country is how a trip goes bad. A cover this light and this small makes the decision easy: it goes in the pack and stays there.

Fitting it

Choose the size by your pack. The Medium fits packs of 50–70 L; the XS and S suit daypacks and smaller hiking packs, and the L suits large multi-day packs. The cover dimensions for each size:

• XS: 20 x 32 x 45 cm
• S: 22 x 35 x 58 cm
• M: 28 x 35 x 65 cm
• L: 30 x 40 x 70 cm

If your pack sits between two sizes, we'd go up a size: a cover that stretches tight over a full pack leaves the bottom exposed, while a slightly roomy one cinches in with the elastic hem. An elastic edge with a cord lock pulls the cover snug around the pack, and on the S, M and L a keeper strap runs across the harness to stop the wind lifting it off.

How it keeps the rain out

The fabric is 30D Ultra-Sil, a light nylon woven with CORDURA yarns for strength, siliconised and coated inside with polyurethane, with a hydrostatic head above 2000 mm. Because the cover has no seams across the top, there is nothing to tape and nothing to fail. A drainage hole in the base lets out any water that finds its way in from the back.

A pack cover protects the top, sides and front. In driving rain, some water can still reach the pack through the gap between your back and the harness, so keep the sleeping bag and spare clothes in dry bags inside for the full belt-and-braces setup.

Weight

XS 57 g, S 85 g, M 113 g, L 130 g. Packed in its sack, the M is 29 x 7.6 x 7.5 cm, about the size of a drink bottle, and the XS is 25.8 x 6.3 x 6 cm. The sack is sewn to the cover, so it cannot blow away while you are wrestling the cover on in a squall.

We stock it in Pacific Blue in every size, and in Lime in the L.

Looking after it

Shake the cover out and hang it to dry before it goes back in its sack. Rinse off sand and salt after coastal walks, and keep it away from sharp pack buckles when you stuff it away.