There aren't any pics of the flask without the funnel, is there some sort of long stem that the cap screws onto? Can you leave the funnel behind if you wanted, or does it provide some sort of protection for that stem? Looks like the funnel inverts to filling mode, so is it permanently affixed?
scopeNevermind, good video on Vargo website. Funnel appears to be removeable, but weight should be minimal and likely adds some protection for the protruding spout.