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Black Diamond Cosmo 300 Headlamp · Octane

Black Diamond Cosmo 300 Headlamp · Octane

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Color: Octane
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Product details

With 300 lumens of power housed in a super compact, watertight body, the Cosmo 300 is perfect for urban adventures and overnighters in the woods. The Cosmo's new, compact body, is more ergonomic with a lower profile for improved balance, and the updated user interface includes a second switch for easy lens selection. In addition, the updated optical efficiency not only provides brighter light, but also saves battery life. And thanks to its watertight construction, the Cosmo keeps lighting the way whether you're forced to bike home in the rain, or you're hiking back to camp in an unexpected downpour.

One size
Age Group
Average Run Time
High: 4 hrs. 15 min.; low: 200 hrs.; reserve: 24 hrs.
3 AAA (included)
Beam Distance
High: 75; low: 8 meters
Brightness Levels
Bulb Detail
White / red LED
IPX Rating
Intended Use
Light Output
High: 300; low: 4 lumens
Max Beam Distance (m)
75 meters
Max Light Output (Lumens)
300 lumens
Water Resistant
2.9 oz
Expert Q&A
Quick, accurate answers from Curated experts to the frequently asked questions
What is the brightest black diamond headlamp?
Currently, the Icon 700 is Black Diamond's brightest headlamp. It emits up to 700 lumens and runs on 4 AA batteries. Run times range from 7 hours on high to 190 hours on low. The Icon 700 has an IPX 67 waterproof rating, which means that it can be submerged up to 1 meter for up to 30 minutes.
Camping & Hiking Expert Will ShawCamping & Hiking Expert Mary ACamping & Hiking Expert Addi Srednick
by Will Shaw on July 1, 2022 · view 2 other answers
Black Diamond Cosmo 300 Headlamp · Octane
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Top reviews
Would an expert recommend this for you?
Amy B
Amy B
Verified camping & hiking expert
Reviewed Jul 13, 2022

With 300 Lumens, this compact, low-profile headlamp has six different modes. It has a digital lockout feature to avoid coming on when stored in pocket or pack.