{Revives a Necro post with a twinkle in his eye}
Hi All!
Don't have a chance to get around here much, but I found this post while searching for the exact same info. I have a Yihua 853D and it came with a 907C handle. It died.
Enter the circus clowns. Info on this little beast is hard to come by. Yihua has release numerous versions; the 853D+, 853D++, 853D USB, 853D USB 2A, 853D USB 3A, etc ad nauseum.
I finally got someone at the company (their service is surprisingly good for a Chinese based supplier/vendor) to explain this handle. It was used only on this machine: 853D (1A) <- It doesn't SAY that anywhere, but that's what they called it) which has a Solder / Hot Air / Power supply to 35v / 1A (surprise!). Actually relatively well built for such things.
The 907C handle is ESD rated. The differences between it and the 907A (widely used / available) is the "C" has a silicone cord and is ESD rated, otherwise they are the same.
I got mine on Ebay in '17 or '18, but it may never have been for direct US sales although it's wired for it, so ... In any case, the 907A will substitute directly or you can use the parts to fix your "C" model.
They don't carry the 907C in the US inventory and offered me a "Special price of $9.99 USD" (very reasonable) but shipping would be $30, so I declined as I'm in the process of upgrading and $40 for a backup doesn't make sense to me. Besides, I suspect the problem is a cable break which of course I could 'handle' (sorry for the pun ...

)
Hope this helps some poor soul looking for a 907C. Their contact info is: customerservices.yihua@outlook.com in case anyone needs it.