DentonDoc wrote on Nov 21^st, 2010 at 8:30pm:

Yes, I know it won't fit inside an altoid tin, but does anyone have experience with any   (You need to Login or Register products.  Something like this might even be useful when you find yourself in a backwater area on day drips (even if you don't otherwise filter). dd

I've got one of those filter straws in my gear, though I've never used it. If I remember correctly, it was around $10 at cabelas - pretty similar to the one in the link you posted.