[nutmeg]

I believe klicks/clicks were first used in WWII. They were behind enemy lines and used them to identify who was friend and who was foe in the dark. A small noisemaker with a distinctive sound. Paratroopers used them I think.

I believe a klick is now a certain distance but I'm not sure how far. The term was used in Vietnam a lot. Might possibly be the distance you could hear the klick. I don't know if they used anything like that for identification in Vietnam.

Thank you for this info!

[Rodney Dangerfield]

Klick is an abbreviation for Kilometer