Packable Rain Jacket: 3 Light Shells for Travel Compared
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A packable rain jacket needs to fit beside everything else in your daypack when the rain stops. For city walks, hikes and boat days, the useful question is what you prioritise: less weight, ventilation or a shell that folds into its own pocket.
Quick answer
Checked on 21 October 2026. Choose Outdoor Research Helium UL for the lowest weight here, provided you can accept no vents. Rab Downpour has underarm vents and higher published ratings than Black Diamond, and weighs 377 g in size M. Choose Black Diamond Fineline Stretch for vents and pocket packing, with a limitation in prolonged downpours reported by OutdoorGearLab.
All 3 picks at a glance
Outdoor Research Men's Helium UL Jacket
Its chest pocket doubles as a stuff sack. Read more
Rab Men's Downpour Waterproof Jacket
Underarm vents give you an airflow option during activity. Read more
Black Diamond Men's Fineline Stretch Shell
Combines pit zips with storage in its right-hand pocket. Read more
How we compared them
The NomadsToolsLab team read the three maker pages on 21 October 2026 and checked each Amazon US page with a US address. The comparison covered weight, waterproof layer, ventilation and packability. The NomadsToolsLab team found that the lightest jacket, Outdoor Research, is the only one without vents. Rab publishes higher ratings than Black Diamond, but only Black Diamond combines vents, published ratings and pocket storage.
Weight, waterproof layers, vents and packing
The waterproof layer belongs beside weight in the comparison. Outdoor Research lists Dermizax, Rab lists Pertex Shield and Black Diamond lists BD.dry, but those names alone do not establish how the jackets compare in prolonged rain.
Rab lists 20,000 mm waterproofing and 20,000 g/m2/24h breathability, while Black Diamond lists 10,000 for each measure. These are maker lab figures, not promises of real-world performance.
The three jackets side by side
| Jacket | Weight (maker) | Waterproof layer | Pit zips or vents | Packs into own pocket |
|---|---|---|---|---|
| OR Helium UL | Weight (maker): 5.7 oz (162 g) | Waterproof layer: Dermizax 2.75-layer | Pit zips or vents: Not listed | Packs into own pocket: Yes, chest pocket |
| Rab Downpour | Weight (maker): 13.3 oz (377 g, M) | Waterproof layer: Pertex Shield 2.5-layer, 50D (20,000 mm, 20,000 g/m2/24h) | Pit zips or vents: Underarm vents | Packs into own pocket: Not listed |
| Black Diamond Fineline | Weight (maker): 320 g (reference size not stated) | Waterproof layer: BD.dry 2.5L (10,000 mm, 10,000 g/m2/24h) | Pit zips or vents: Pit zips | Packs into own pocket: Yes, right-hand pocket |
From the makers' pages, read on 21 October 2026: Outdoor Research, Rab and Black Diamond.
Outdoor Research Helium UL: prioritise low weight
Outdoor Research Men's Helium UL Jacket
Choose the Outdoor Research Helium UL Jacket if carrying less weight matters most, because it is the lightest shell here, but it has no pit zips or vents. BetterTrail found sweat builds up during sustained activity, which matters if your rain cover will also be your hiking shell.
The chest pocket provides a defined packing place when the jacket comes off. Its adjustable hood includes a brim wire, while the waterproof fabric has fully taped seams.
Rab Downpour: prioritise ratings and ventilation
Rab Men's Downpour Waterproof Jacket
Choose the Rab Downpour Waterproof Jacket if you want published waterproof and breathability figures alongside underarm vents, because Rab provides both, but it weighs more than the Helium UL. Rab does not state that it packs into its own pocket, and OutdoorGearLab also notes that limitation.
Plan space in your bag without relying on a built-in stuff pocket. The hood has a stiffened peak, giving you another detail to consider alongside the fabric ratings.
Black Diamond Fineline Stretch: prioritise vents and packing
Black Diamond Men's Fineline Stretch Shell
Choose the Black Diamond Fineline Stretch Shell if you want pit zips and pocket packing together, because it offers both, but OutdoorGearLab found a limitation in prolonged downpours. Its reviewer got slightly wet and found it less water resistant than the best shells in that comparison.
The right-hand storage pocket includes a carabiner loop, and the hood is helmet compatible. Black Diamond lists a weight of 320 g; the product page does not identify a reference size.
Choose the compromise that fits your travel
For a jacket carried through city days, start with whether low weight or pocket packing matters more to you. Helium UL offers both, but adds no vents for the moments when walking becomes sustained activity.
For hikes and boat days, consider airflow and rain duration separately. Rab has underarm vents and higher published ratings at 377 g in size M. Fineline has pit zips and pocket storage at a listed 320 g, with no reference size specified. Packing the rest? See our packable daypacks and dry bags for travel.
- Helium UL is the lightest here and packs into its chest pocket, but has no vents.
- Rab has underarm vents and higher published ratings than Black Diamond. Rab does not state that it packs into its own pocket.
- Black Diamond Fineline has pit zips, published ratings and storage in its right-hand pocket.
- All three makers also sell a women's version. This comparison covers the men's jackets.
Watch: the Fineline Stretch Shell up close
For a closer look at the Fineline Stretch Shell, see Enwild's video, “Black Diamond Fineline Stretch Shell” (2026).
Video by Enwild.
See the Black Diamond Fineline on Amazon.
FAQ
Which jacket is the lightest in this comparison?
Outdoor Research lists the men's Helium UL at 162 g. That makes it the lightest of these three jackets.
Which jackets pack into their own pocket?
Helium UL packs into its chest pocket, and Fineline Stretch stows into its right-hand pocket. Rab does not state that Downpour packs into its own pocket.
Which jackets have ventilation zips?
Rab Downpour has underarm vents, and Black Diamond Fineline Stretch has pit zip vents. Outdoor Research Helium UL has no pit zips or vents.
Does the Fineline Stretch have a limitation in prolonged rain?
OutdoorGearLab reported that its reviewer got slightly wet during prolonged downpours. It found the Fineline less water resistant than the best shells in its comparison.
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