6. What's the outer diameter of the F5's sound tube?
A: The outer diameter of the F5's sound tube is 6.0mm in maximum. If you wish to buy spare eartips for it, it's suggested to buy the eartips whose hole size is 5.0mm. For silicone rubber eartips, the hole sizes from 3.5mm to 5.0mm are basically all fit on the F5.