example 1: If you are using a 3 liner or 3 round shader you need a 3 Round tube.
example 2: If you are using a 7 liner or 7 round shader you need a 7 Round tube.
example 3: If you are using a 5 flat needle or 5 magnum shader you need a 5 flat tube.
example 4: If you are using a 7 flat needle or 7 magnum shader you need a 7 flat tube.
This works for all groupings except stacked mags, because these are in 2 rows you need to apply the following:
example 1: If you are using a 9 stacked mag needle you need a 5 flat tube.