Is the 6 L size enough for a trip's clothes?

For a short trip or a few layers, yes. A full week of clothing usually needs a larger size, since 6 L fills quickly with bulky items.

No. The PU-coated nylon is water resistant and handles damp, but it will not keep gear dry in sustained rain.

How much does it weigh?

About 110 g for the 6 L version, which is light enough for weight-conscious backpacking.

What can I fit in it?

Clothing, a sleeping bag liner or other soft gear. It is not padded, so it offers no protection for fragile items.

Is $39.95 a good price?

It is the only new price listed as of November 7, 2026, at Amazon, so there is no cheaper new listing to compare it with right now.

Does it come in other sizes?

Sea to Summit makes the Ultra-Sil Compression Sack in a range of sizes. This listing is the 6 L version.

Where is the Sea to Summit Ultra-Sil Compression Sack cheapest?

At Amazon, for $39.95, as of our latest check.

Sea to Summit Ultra-Sil Compression Sack

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$39.95at AmazonObserved at 4:03 AM

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Our take on the Sea to Summit Ultra-Sil Compression Sack

The Ultra-Sil Compression Sack is a lightweight stuff sack that squeezes clothing and soft gear down to a fraction of its packed size. The 6 L version weighs about 110 g and uses 70D PU-coated nylon with a flip-top lid that keeps the straps from tangling. It is water resistant, not waterproof, so it suits clothes and gear that can take damp, not items that must stay dry. At $39.95 at Amazon as of November 7, 2026, it is the only new price listed, so there is no cheaper new option to compare against right now.