Black Diamond Cosmo 350-R Review (2026)

Name: Black Diamond Cosmo 350-R
Brand: Black Diamond
Price: 40.00 USD
Availability: InStock
Rating: 8.0 (1 reviews)

The Black Diamond Cosmo 350-R fills the gap between budget single-use battery headlamps and premium rechargeable options: at $40 with USB-C charging and AAA backup, it delivers rechargeable convenience with the field-resupply flexibility of disposable batteries, under the coverage of Black Diamond's lifetime warranty. For hikers upgrading from a basic AAA headlamp for the first time, or anyone who wants the most accessible entry point into rechargeable headlamps from a reliable brand, the Cosmo 350-R is the straightforward answer.

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$40 retail

8.0

/10

TrailCraft Score

What Works

$40 makes rechargeable capability accessible at a budget-friendly price
USB-C charging uses the same cable as most modern phones
Accepts 3x AAA batteries as backup — dual power flexibility at this price is uncommon
2.6oz is lightweight for a dual-power headlamp
Black Diamond lifetime warranty provides strong coverage at this price point

Limitations

350 lumens is adequate for camp and casual hiking but not technical terrain
Flood-only beam with no dedicated spot mode
IPX4 splash-resistant only — not suitable for immersion

Specifications

Weight2.6 oz / 74g

Max Lumens350

BatteryRechargeable Li-ion (USB-C, included); also accepts 3x AAA backup

Beam TypeWide flood with dimming

WaterproofIPX4

WarrantyBlack Diamond limited lifetime warranty

Score Breakdown

Brightness

7.6

Battery Life

8.4

Weight

8.8

Ease of Use

9.2

Value for Money

9.4

What Sets It Apart

The combination of USB-C recharging and AAA backup at $40 is the Cosmo 350-R's defining value proposition: most headlamps at this price offer one or the other. Black Diamond's decision to include both in an entry-level model reflects the practical concern that a dead rechargeable battery in the field is a real scenario, and having AAA fallback capability eliminates it without requiring a second headlamp to be carried as backup.

Black Diamond's lifetime warranty applies to the Cosmo 350-R the same way it applies to the brand's $130+ models. At $40, this warranty commitment is unusual — most headlamps at this tier carry 1-2 year warranties. For a product that should last years with normal use, the lifetime coverage meaningfully reduces the long-term cost of the initial investment.

350 lumens, USB-C rechargeable, $40 — the easiest entry point into rechargeable headlamp ownership

Who This Is For

The Cosmo 350-R is right for: first-time rechargeable headlamp buyers, backpackers who want dual-power flexibility at a budget price, and hikers who want USB-C convenience backed by Black Diamond's warranty and brand reliability.

A note on pricing: Prices are current as of July 2026 and may change. Some links are affiliate links.

How It Compares

Ranks #12 of 14 headlamps in this category.

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Common Questions

How is the Cosmo 350-R different from the Spot 325?

The Cosmo 350-R is rechargeable via USB-C; the Spot 325 uses only AAA batteries with no built-in rechargeable. The Cosmo has slightly higher output (350 vs 325 lumens). Both accept AAA backup. The Spot 325 has IPX8 waterproofing; the Cosmo has IPX4.

Is $40 for a Black Diamond headlamp a good deal?

Yes — Black Diamond's entry-level headlamps are well-made relative to unbranded competitors at the same price, and the lifetime warranty provides coverage most budget headlamps don't offer.

Can it charge from a power bank?

Yes — USB-C output from a power bank charges the Cosmo 350-R the same way as any USB-C device. Carrying a small power bank for phone and headlamp charging on multi-day trips covers both devices.

Is the Cosmo 350-R good enough for backpacking?

Yes, for most backpacking use — camp tasks, trail navigation, and tent reading. For technical terrain at night or trail running, a brighter headlamp is the appropriate upgrade.