Hi, just get the adapters/converters for the IE 300/600/900, AKG N5005, etc. It should work with any MMCX connection, though it'll be loose and prone to falling off, at least with some of them.

Like the OKSC one on Amazon is loose with the IE 200 and my FiiO UTWS3/5 TWS adapters, it falls off easily with certain angles and movements. But it works pretty well, just don't move too fast or tilt your head that much.

Try buying from Amazon UK (Amazon USA, Amazon Japan, et cetera also ship to some places Europe), lol.

Here's more info on TWS adapters like the FiiO UTWS3/5, KZ AZ09 Pro, etc. alongside adapters/converters, AptX Adaptive dongles (KB9P, YET-T10P, etc.), and so on needed for them: https://www.reddit.com/r/HeadphoneAdvice/comments/11565qg/need_help_buying_a_bluetooth_wireless_adapter_for/j9033u7/ and https://www.reddit.com/r/HeadphoneAdvice/comments/10hfuxn/wireless_earbuds_for_gaming_with_plugin_to/j58i33j/

Here's a more direct link for the adapters/converters required for the different IEMs and headphones: https://www.reddit.com/r/HeadphoneAdvice/comments/t3v7wp/looking_to_make_my_arias_wireless/hyv14dn/

Don't forget the versions (adapters/converters for the IE 300/600/900, AKG N5005, etc.) from AliExpress, there's a few other ones there.

With quality control of Chinese IEMs, AliExpress shipping times, see here for a bit more info: https://www.reddit.com/r/headphones/comments/10sna0p/i_have_it_engrained_in_my_mind_as_an_american/j7395yr/ and https://www.reddit.com/r/headphones/comments/zav570/is_hifigo_a_scam/iynrt65/

For the cables, you can ask custom cablemakers like XINHS on AliExpress to add microphones, different colors, longer/shorter length, etc. to the cable. Make sure to specify what you want, it might be extra costs though.

Here's a bit more info on how to get cheap cables and also customized cables to your liking: https://www.reddit.com/r/HeadphoneAdvice/comments/z931n3/mmcx_cables/iyfic2p/ and https://www.reddit.com/r/HeadphoneAdvice/comments/10hg005/help_finding_cables_for_sennheiser_ie_600/j58j4t8/

Extra info on wired IEMs/headphones/Bluetooth/et cetera: https://www.reddit.com/r/headphones/comments/11a550d/how_can_i_learn_the_basics_about_soundheadphones/j9r9r48/