Yes, it's the FiiO L16 and it works with the X5-1's separate 3.5mm TS coaxial port. Yes, I know, I know, it's a stereo TRS cable meant for line-out connections and not a shielded 75 Ohm coaxial standard cable. It does work though as the signal and ground line up with the pin outs.
For the Cayin i5 you need to use their USB C to coaxial cable as they don't have a 3.5mm coaxial port for the i5. There's plenty of information on the i5 thread if you do a search for coaxial output, or just ask there (Andy Kong usually replies rather quickly).
thanks for the quick reply. yeah, i also asked and did a search in the i5 thread. I also looked at the N6 thread and found some answers. Someone did mention that the i5 also has Coax out - but now i have the pin configuration (TS Plug - Data at Tips, Ground to Sleeve) for the cable - just need Andy to confirm the Coax for i5