Depends on your ear canal and preferences. Hard to say in one word, but people say good things about: JVC Spiral Dots, SpinFit, Comply etc. On my side I found bi-flange tips from the stock package so far the most suitable. Ordered SpinFit CP240-M to check them out as well.

Regarding the fit for FH5, I have tried all the stock eartips - none is the best, but quite ok were voice L and foam. I tried also Comply foam 400 and quite like them, but they produce quite dark sound with slightly overpowered bass. I tried also SpinFit M, but they are too small for me...

No problem ;-) This is my first DAP, so I cannot really compare, but I enjoy it and got better with latest firmware. So positive improvement trend ;-)

I have N5iiS for a month or so already with latest 1.4en firmware. Indeed, there are some issues, but overall it is a very good DAP! Don’t bother too much. There is a delay in UI hardware buttons or lack of response if you wish, some UI drawbacks like almost impossible to move the track forward...

Indeed, it could be kind of the problem and possibly quite common. Time to time I feel that the sound is little imbalanced, but when I push a bit further right headphone it becomes more in the centre of my head, weird, but could be also related to that fact you've mentioned.

Question is if EQ degrades the quality of the sound, some amps have direct mode not without the reason I guess and on some DAPs EQ is disabled in Audio Priority mode?

I have LC-2.5C from original FiiO Aliexpress store with FH5 and I am very happy. Didn't notice any significant sound change, but it looks great and has very good built quality!

Yes, I know. One of the member of local headphone forum said that CP145 SpinFit is the best one in terms of sound and Symbio's in term of fit and isolation.

Thanks a lot. There are also hybrid tips like Symbio (silicon with foam), I heard worth to try...

Hello, I've just pulled the trigger for FH5 pairing them with Cayin N5iiS over LC-2.5C cable. Works very good, but have question to more experienced forum/thread members which tips most of you are using with FH5? I've tried almost all of them included in the package, none work perfect for me. I...

..and I would like to know if N5iiS is also proned to that issue on 2.5mm jack @CayinSupport ?

Just upgraded to 1.4en for iiS and it seems to be snappier and with much better power management. Sounds very good as well on my F9 and new cable. Treble is smooth like sand :wink:, bass very punchy, maybe lack of some sub-bass, but it’s a matter of IEMs IMhO.

Do they have shorter nozzles than F9 if you happen to know?

What's the main reason to drive the nozzle change on FH5?