It has a triangular shape so you can thread it through the end of your cleaning rod without a lot of bulk at the tip; this allows it to pass through the entire barrel of the instrument without getting hung up on anything

: Thread it through the cleaning rod and the cover the top of it with the bigger side

I really like the tapered cut so you can thread it easily through the cleaning rod.

However, I just stick this through the hole in my cleaning rod (comes with all flutes), and it works well