PSU regulator PCBs identifying help needed

I've been given this PCB as a gift but can't find a topic that deals with it, so can anyone point me to right topic where I can find details abot using them, pleas.
Thanks in advance.
 

Attachments

  • IMG_20210322_122133.jpg
    IMG_20210322_122133.jpg
    540.6 KB · Views: 100
  • IMG_20210322_122036.jpg
    IMG_20210322_122036.jpg
    772.5 KB · Views: 103