Tested the technology first with the KZ ZS 10 Pro which i really liked. The KZ convinced me enough to upgrade to Fiio’s FH9. Everything is perfect, a KZ upgrade on all aspect (comfort, sound, look, materials, options). It is a master W shape type of sound signature, the bass-mid-high simply sparkle on every aspect. They are liquid compare with the dry KZ, I like them much. The 13mm DD is punchy, the BAs cover the rest. It is a perfectly made hi end techno piece of jewel. I can’t imagine any other iem beating this one, even at third the price. The package include everything you can think of to customise them as your taste. Very very impressed.