www.banggood.com
https://www.banggood.com/Wholesale-Arduino-Compatible-SCM-and-DIY-Kits-c-2153.html
Mode 4:
Center to both sides
Long press 1 second:
5 speed adjustment, the right side of the LED will
correspond to the display (the default value is 3, 1-5 grade value is
slower)
Long press 3 second:
left and right channel switching, 3-4 column LED
lights for L left channel, 8-9 column LED light for R right channel