In-depth review
Black Diamond Cosmo 350 Review (2027)
In-depth review of the Black Diamond Cosmo 350: dual-fuel power, IPX8 waterproofing, red night vision, and a battery meter at a budget price.
Black Diamond Cosmo 350
A 350-lumen dual-fuel headlamp with IPX8 sealing, red night vision, and a battery meter.
Our verdict
The Cosmo 350 is the budget lamp with flagship manners: IPX8 submersion sealing, dual-fuel power from AAAs or Black Diamond's rechargeable pack, red night vision, dimming, and a battery meter, all under 3 oz. Output caps at 350 lumens, which covers camp and trail honestly. For wet trips and mixed battery households, it is the value pick to beat.
What we like
- Dual-fuel: 3 AAA batteries or the BD 1500 rechargeable pack
- IPX8 waterproofing, tested submerged
- Red night-vision mode with dimming and strobe
- Integrated battery meter and digital lock mode
What to watch out for
- 350 lumen ceiling suits camp and trail, not high-speed descents
- Rechargeable BD 1500 pack sold separately
- Two-button sequences take a session to learn
What owners report: Black Diamond Cosmo 350
Synthesized from recurring themes in long-term owner feedback.
Most praised
- Waterproofing at a budget price survives submersion that pricier lamps cannot claim
- The battery meter and lock mode are features usually missing at this price point
- Dual-fuel power accepts AAA cells or the maker rechargeable pack, whichever is at hand
Common complaints
- Output suits camp and trail pace rather than fast descents
- Two-button sequences take a session to learn by feel
- The rechargeable pack is an add-on cost beyond the shelf price
Who it is for
Backpackers and campers who want waterproof, dual-fuel reliability without a premium price.
Sealing and build
IPX8 is the headline: the Cosmo is waterproof-tested to operate submerged at over a meter for 30 minutes, a rating budget lamps almost never carry. The compact polycarbonate body and multifaceted lens keep the package simple and tough.
Dual-fuel power
Run the included three AAA cells, or fit the BD 1500 lithium-ion pack (sold separately) for rechargeable use; the lamp accepts either without modification. An integrated meter shows remaining power, and a digital lock prevents the classic dead-lamp-in-the-pack outcome.
Light and limits
Three hundred fifty lumens with a 64 m maximum distance covers proximity work and moderate trail pace, with red night vision that dims and strobes. Speed descents and big route-finding are beyond the brief; this is a camp and trail lamp priced accordingly.
Key specifications
- Output
- 350 lumens
- Weight
- Approx. 2.9 oz
- Power
- 3 AAA (included) or BD 1500 pack (optional)
- Max distance
- 64 m
- Water resistance
- IPX8
Sources: Amazon product listing, Black Diamond product specifications, Manuals.plus product documentation
Also consider
Black Diamond Spot 400
The classic do-everything lamp, now in dual-fuel form.
Why consider it: More output and the same dual-fuel system for a step-up price.
- Max output: 400 lumens
- Beam distance (max): 100 m
Petzl Tikka
A 350-lumen compact headlamp at 94 g, with red lighting and hybrid AAA or CORE battery power.
Why consider it: Petzl's simpler hybrid classic with a wider flood for camp tasks.
- Output: 350 lumens
- Weight: 94 g
Sources: Amazon product listing, Petzl product specifications
Research-based assessment. TrueGear has not hands-on tested this product; this evaluation synthesizes manufacturer specifications, retailer documentation, and published expert reviews.
Questions, answered
Can the Cosmo 350 use a rechargeable battery?
Yes. It runs on three AAA batteries or Black Diamond's BD 1500 rechargeable pack, sold separately.
What does IPX8 mean here?
Black Diamond rates the Cosmo IPX8: waterproof-tested to operate at least 1.1 meters underwater for 30 minutes. Dry the battery compartment after submersion, per the manual.