FIFINE Wireless USB Receiver for K025/K031B/K037/K037B

There are a total of 3 versions of this receiver with a USB jack (which is for plugging into PCs/laptops). So please carefully choose the variants of when did you buy the FIFINE wireless system that you're using and whether the highest frequency of the transmitter that you will pair with is below 600MHz.  When you get the correct receiver, you still have to pair it with the FIFINE transmitter that you have already been using. Find the model of yours and follow the tutorial video to pair the new receiver with the old transmitter. K031B from 3:10 to 4:00  K026 (the same transmitter as K025 but with a USB receiver) from 2:50 to 3:41