The Black Diamond Sprinter is very clearly the result of a thoughtful and practical design process. At first, the use of a separate battery compartment seems a bit odd in a headlamp of this size. However, this helps to balance the headlamp and significantly reduce any movement or bounce of the lamp. The Sprinter therefore wears and feels lighter than its published weight would suggest. The Double Power LED provides focused illumination at all brightness settings, and is easy to adjust while running. The Sprinter also features a blinking red LED on the battery compartment to further enhance visibility.

The Sprinter has a published battery life of 6 hours on full brightness and 42 hours on the lowest setting. This is certainly less than most headlamps, but is adequate for runners who are getting out for an hour or so in the morning or evening. Any gains in convenience from not having to change batteries are offset by having to charge the headlamp about once a week.

Runners who are out every day in the pre-dawn or post-sunset hours, but don’t otherwise do much running in the dark, will likely find the Sprinter to be the perfect headlamp. It is probably not the best choice for runners who want a more general-purpose light. 

Comfort
The Sprinter is an extremely comfortable headlamp due to its excellent balance. The straps are thinner than most but nonetheless hold the lamp in place without excessive tension. The strap over the top of the head is easily removable to further reduce weight, and the Sprinter does not bounce or move around more when used without the top strap. The Sprinter is also extremely comfortable when worn around the waist (obviously without the top strap) as a secondary light during night running.

Brightness
At 130 lumens max output, the Sprinter is not the brightest light on the market. However, the output is very coherent and focused, making it highly effective on both roads and trails, even on the lower illumination settings. 

Ease of Use
The Sprinter is extremely simple and straightforward to use. The two buttons on the lamp body—one to control power and brightness, and a second to temporarily switch back to full brightness—are large enough to easily operate. However, the button on the battery compartment that controls the rear red light is small and difficult to press, especially with gloves on. There is also no way to determine if the rear light was deactivated without removing the headlamp. A switch with easily identifiable on/off positions, or some other tactile mechanism, would be simpler.

Features
The feature set of the Sprinter is minimal but gets the job done. The lamp has a single output mode with variable brightness, a strobe setting, and a rear blinking red LED to enhance rear visibility. One additional feature of note is the ability to temporarily switch back to full brightness with the side-mounted switch on the lamp body. This provides temporary additional visibility when, for example, approaching an oncoming car. The Sprinter does not have a battery level indicator. 

Run time
The run time is clearly the weak point of the Sprinter, and is significantly less than other headlamps of comparable weight and output. The shorter runtime also limits the versatility of the headlamp. For example, it can’t really pull double duty as a camping or backpacking headlamp, or be used through the night during an ultra-marathon. The battery life can be extended by turning off the rear red light, but because the rear light defaults to on, this can be easy to forget about.