That tube is plugged in the middle, so there are two compartments.
At the right is a compartment for a piece of sandpaper, so one always has at hand a guaranteed reliable striking surface. At the left is the match compartment (indicated by the '+' sign), with a capacity of eight kitchen matches. The holder looks watertight to me, and would surely float.
This item reminds me of a story.
I'll stash this in the tackle box where I keep miscellaneous items of camping gear.
# # #
# # #
