If you are not electric guy you will have problem with connecting fans on adapter !

I recommend you that you take pc power suply out of pc box ! Put power suply near your grow box and connect fans like usually on pc !

Very simple and you don't need to waste money on adapter !

Picture ! !

PC suply is connected on home/local power net and pc fans goes on that suply ! I have also connected 4 switches for 4 fans that i can turn them on/off as wanted !