Backpack Mushroom Liner Bag Review: Will it keep your sleeping bag dry in the rain?
30-second verdict
A backpack mushroom liner bag is a clear, wide-mouth plastic bag you put inside your pack to protect your sleeping bag and clothes. It costs about NT$7. It covers what a rain cover misses, but only if the bag has no holes and the top is rolled shut. In long heavy rain, give the sleeping bag its own extra layer as well.
Good for
- Overnight hikes and plum-rain-season treks, or anyone who wants a cheap extra waterproof layer.
Not for
- Anyone who wants one bag to get them through days of downpour, or who needs a durable dry bag that lasts for years.
Buying Guide Notes · First published:
Compiled from public sourcesWritten using official specs and user feedback.
Pros
- ＋ A clear, wide-mouth liner, so you can see what is inside at a glance
- ＋ PTT and Mobile01 hikers often use mushroom bags or big plastic bags as inner waterproofing; Reddit also favors a liner plus a rain cover
- ＋ At NT$7 with 2,000+ sold, an extra liner layer costs almost nothing
Cons
- － Forums agree a rain cover alone will not keep the pack bone-dry; a liner can also tear or let water in at the roll-top
- － Check the thickness, real size and pack count in the options before you order
- － Few long-term reviews of this exact model; on days of heavy rain, wrap the sleeping bag in one more layer or use a thicker dry bag
Specifications
| Product | Backpack waterproof mushroom bag / pack liner |
|---|---|
| Look | Clear or translucent soft plastic, wide mouth, mushroom-cap shape when opened; folds flat |
| Role | Internal pack liner for wet/moisture—not an external rain cover |
| Shop claims | Waterproof/moisture-proof gear protection; often two size options |
| Common uses | Line the pack, load sleeping bag and dry clothes, roll-and-tie the extra mouth length |
| Price note | About NT$7 (promo prices change) |
| Sold note | About 2,000+ sold |
| Not yet widely tested | Exact thickness/size charts; seepage in hours-long storms |
Sources and verification status
Verification status: compiled from public sources; not hands-on tested
Data updated:
What it is
Taiwanese hikers call it a "mushroom bag" because the top flares out like a mushroom cap once the bag is full. It is soft, thin plastic that folds small. Line the main compartment with it, pack your sleeping bag and warm layers inside, then roll the top closed. The store page offers two sizes but lists no thickness or durability data.
Why packs still get wet under a rain cover
A rain cover cannot cover the back panel, and water runs in along your back and shoulder straps or pools at the bottom. Hikers on PTT and on r/backpacking say the same thing: the cover handles the outside, and a liner protects what is inside.
Choosing a size
The liner should be deeper than your main compartment so there is enough extra at the top to roll it closed. Measure your pack's depth and circumference, or go by its capacity in liters, then compare with the size options.
How to pack it
- Push the liner all the way to the bottom of the pack.
- Put in the sleeping bag first, then warm layers and spare clothes.
- Twist or roll the top two or three times and tuck it under.
- Keep anything that can get wet outside the liner, and pad sharp items such as tent poles and pot edges.
Durability
Reviews of cheap liners are mixed. Hold it up to the light before every trip, replace it when it tears, and carry a spare because it is so cheap. When the plastic turns white at the folds or goes stiff, it is aging and should be replaced.
On arrival
Unfold it, check for holes against the light, inspect the heat-sealed bottom seam, and test-fit it in your pack. If it is damaged or the wrong size, take photos and request a Shopee return.
Alternatives
A rain cover keeps off dirt and light rain but is not enough on its own. Roll-top dry bags last longer but cost and weigh more. Heavy-duty trash bags or compression sacks are easy to find, but you cannot see through them.
FAQ
Is it rainproof?
It is an inner layer. A torn bag or an open top will let water in.
Liner vs. rain cover?
The cover goes outside and the liner inside. Using both is safest.
Reusable?
Yes. Check it for holes each time.
Where to buy
Prices change often—recheck the amount and options before checkout.
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