HXSJ Wired Keyboard and Mouse Set 61 Keys Gaming Keyboard 7 Colours backlight 4 DPI Stages White/Black Mouse

4-1.Volume adjustment: FN+R key is volume reduction,5 levels adjustable; FN+ l: Backlight off/on, cyclic switching;4-3. Compound function key switch: FN+1! key=F1   FN+2@ key=F2 FN+3# key=F3  FN+4$...