7. What are the differences between the audio filters? And how to change it?

The flagship FH15 comes standard with three interchangeable audio filters. Each audio filter has its own damping and filter density, allowing you to choose between three different sound signatures.

Red tube--boosts bass, achieves deeper insertion in ear canals when working with bi-flange or triple-flange ear tips

Black tube--presents detailed treble with high resolution

Green tube--presents great treble details in every music note

*The black audio filter comes pre-installed. Other filters are included as accessories