F2 Flashlight Brass

Naturally that's totally up to your preference but how to make the choice?  

Start this way.  Ignore the brand and the numbers and letters behind it and focus on the 5000k and 4500k.  That's the color of the light.  But how do you compare that to something you know?

It's easy.  Think about an old incandescent light (most light bulb's these days try to mimic that color).  Remember what color they are?  Kind of a yellowy white?  That yellowy white color is roughly 3500k.  the lower the number the yellower the light the higher the color the bluer the light..

4500k is just a littler bit bluer than the old incandescent.  It's soft and easy on the eyes but appears a little dimmer than the 5000k option.  

5000k is more intense.  More towards blue it eliminates any yellow and appears to be white light.  It looks brighter and light's up an area better than 4000k (in my opinion)

I used to always recommend going with 5000k when I'm asked.  I prefer its brightness and lack of yellow in the beam.   

However the New 519a 4500k emitter is the latest greatest emitter and isn't very yellow so I'm not sure which one I like best anymore.