I sell my JCALLY JM20 PRO due to lack of usage.
Nice little dongle, can power up to 2V for high impedances headphones - i.e. 300 Ohm Sennheiser HD6XX.
I was using as part of a DAC - AMP chain since it has very clean output at 2V.
Perfect for IEMS too.
This PRO version has also built in EQ (!) which I tried and it works well.

Full review in ASR