i got one of those too!
i don’t know either, but it could be used for many small things
they come with hougen drill bits in them
edit: i have also seen other things come in them, but cant remember what off the top of my head right now
edit again: pretty sure i have seen hilti bits in them too, but longer
My Balder SE1 came in a shorter version of that.
They are generic containers used for a lot of things, including flashlights.
They might be commonly used for drill bit cases or made exclusively for that purpose, but I can't find them sold separately.
Yeah they could. I want them for my small lights, for starters.
if you can get them in different sizes it could be used for a great number of things
I have seen them larger around then 3", and over a foot long... I'm sure someone will come along and post where they can be bought seperate
I thought I remember seeing something similar on county comm at one point…but I remember it being smaller — same design though.
That’s where I’ve seen them, welding rod containers. When you mentioned them being over a foot long, I recalled seeing welding rods in them at the supply store.
We're on the right track now. I saw a long clear one. Here's a long orange one.
Now I need to find short ones sold on their own for cheap.
Hot Max sells their welding rods in longer versions of what I'm looking for.
If you buy a L3 Illumination L10 from SB Flashlights, your light comes in one of those.
Oh… I get it; where do you buy a bunch of empty ones 
“Never Mind”
Have a lot of those in both clear and red, round and square, come in a lot of different variations. All the ones I have came with drill bits or router bits, many different brands. Helps protect the bits from breaking, especially carbide ones.
Are there any markings on it that might indicate the manufacturer? Mine says "PP" on one end and "24" on the other.
It’s called a:
QuadroPack Plastic Sleeve
Here’s the manufacturer (they’re a German company):
Looks like these guys have them:
http://www.ring-plug-thread-gages.com/ti-SW-plastic-sleeves-QuadroPack.htm
Searching for them on Amazon / Uline / Grainger hasn’t scored any hits 
I put in a product request at US Plastics.
Great find! I'll contact the second company tomorrow. I sent another message to USPlastics to let them know what this is called. I like their prices and shipping, and it seems like something they'd carry. Fasttech will get a product request too, which will be a better choice for those of you in other countries...maybe they'll even ship their flashlight hosts in it.
Looks like McMaster-Carr has a few of them, and some similar items:
To buy them from the manufacturer’s U.S. Distributor:
http://www.roselitepackaging.com/pdfs/QuadroPack.pdf
Hexpack look useful too:
I found this on Ebay, with other brush and pen storage:
http://www.ebay.co.uk/itm/Brushes-Pencils-Pen-TELESCOPING-Storage-Organizer-Tube-Carrier-Holder-Case-Box-/121127680448
Better to search for “telescop*” since “QuadroPack” seems a brand name of Rose Plastic:
http://www.beckettplastics.co.uk/packaging/pdfs/Telescopics.pdf
http://pandepack.en.ecplaza.net/quadro-telescopic-plastic-box-package—158043-797190.html
balder HD1 also comes in that case.
it can be used as diffuser too if wanted…