Frequently Asked Questions

Please review the following frequently asked questions, the User's Guide for each product and the product comparison chart.  If you have a question after reviewing this material, please contact us by e-mail or phone.

LEDs and light measurement standards

What is an LED?  

What are lumens, spec sheet lumens and out-the-front lumens?  

What is the ANSI/NEMA FL-1 standard?  

How far can I see with my light?  

What are lumen-minutes?  

Are all white LEDs the same color?  

What is a color rendering index (CRI) and why is high CRI important?  

Why are warm-white and neutral-white LEDs less efficient than cool-white LEDs?  

How long will the LED last?  

Advanced technologies

What is constant power LED regulation?  

Why are your lights calibrated?  

What is burst mode?  

What is visually even brightness spacing?  

What is an optimal beam pattern?  

What is tint control?  

What are Acme threads?  

What is an anti-reflective (AR) coating on the lens?  

What is military Type 3 hard anodize?  

What is black nitride?  

What is Cerakote?  

Operational considerations

What is the logarithmic nature of my eyes?  

What is the practical difference between different light outputs?  

How bright is each brightness level?  

Which beam pattern is best?  

How can I see further?  

How can I see through smoke, fog or murky water?  

How long will the batteries last on each brightness level?  

Why do flashlight runtimes vary?  

How can you achieve the lowest cost of ownership?  

Do you overdrive your LEDs?  

How do I attach a lanyard?  

Batteries

How long will my battery last?  

What's the difference between primary and rechargeable lithium batteries?  

What are 123 lithium primary batteries?  

What are rechargeable lithium-ion batteries?  

What's the difference between 123, 16340 and 16345 batteries?  

What is the difference between 18650 and 18680 batteries?  

Installing accessories

How do I swap bezels?  

How do I swap lenses?  

How do I swap reflectors?  

How do I swap buttons?  

How do I install the universal pocket clip and lanyard attachment?  

How do I install the Clicky-style pocket clip?  

How do I install the external Clicky switch cap O-ring?  

Other questions

What are legacy flashlights?  

How bright is my flashlight?  

Can I use my flashlight as a dive light?  

Why does the flush button not tail stand?  

Where are your flashlights manufactured?  

What are CE, RoHS and WEEE?  


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Trademarks and trade names are the property of their respective owners.
Updated March 2017
www.HDSsystems.com