Black Diamond Cosmo Headlamp Review

A headlamp needs to do one thing, provide reliable, usable lighting without getting in the way or weighing you down.

The Cosmo from Black Diamond aims to do just that. No fancy bells and whistles, just what you need when you need it.

About the lamp

The Cosmo retails for 29.95, comes in 6 colors, and weighs only 3.2 oz while putting out 90 lumens. Burn time is rating at a max of 250 hours, and a minimum of 150 hours, depending on what setting you’re using. The lamp includes two low powered LED’s, one high-powered LED, and one red LED. A strobe function is also included, along with a subtle power meter that turns off seconds after initiating the light. 3 AAA batteries power the glow.

The headlamp is simply designed, with a single button for operating the unit, and a single adjustable strap for strapping it to your head.

Black Diamond Cosmo

What I liked

Simplicity is king when it comes to lighting. A single, easy to find click turns on the headlamp, toggles between settings, and turns it back off. Holding in the button while the lamp is on dims the lamp to your preferred brightness, while repeated pushing initiates the strobe. It’s easy to turn on with gloves or even in the dark when you can’t see a thing.

The light is plenty bright enough for backpacking. A long beam on high allowed me to scan the forest for that late night crunching noise, while soft dual LED’s illumined the inside of my tent with a soft, diffused glow without reflecting back harsh white light. The red LED is sufficient to work with my hands without resetting my night vision.

It’s light weight, comfortable, and the battery life is absolutely fantastic, even with standard Energizer AAA batteries. The band always sat softly across my forehead, without being abrasive, while a quick, easy to use adjustment provided flexibility when taking on and off beanies and hats.

The price is quite low at just 30 bucks, while still providing a solid, sturdy build.

Black Diamond Cosmo

What I didn’t like

So far, I’ve not found anything not to like about this headlamp.

Other considerations

There are currently two versions of this lamp, the newer 2014 having twenty more lumens than the 2013 model, at 70 lumens. It’s a minor difference that I couldn’t find much of a real world difference in.


The Cosmo is an excellent headlamp. A fantastic price, quality build, and plenty of light provides everything you need out of a headlamp. If you’re wanting something you can rely on, that won’t get in the way or break the bank, this is a fantastic choice.

Highest of recommendations



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