18.What's the main difference compairing BTR3K to BTR3 ?

1.BTR3K has cancelled NFC function for framework limitation.
2.The rear clip of the BTR3K is detachable while the BTR3's is integrated
3. The BTR3K is featured with two built-in AK4377A DACs with 3.5mm SE and 2.5mm balanced outputs, which 2 DACs would be working for both 3.5mm and 2.5mm outputs. But for BTR3, there is only one AK4376A DAC for 3.5mm output.