This is a part of my project about reverse engineering the Yamaha TYU-30 toy keyboard ROM pack cartridges. It works as a replacement for the edge connector so you don't have to buy new ones or desolder the original on the keyboard. Prepare some 24-28 AWG wire (I am using stranded CAT6 internet cable), insert into the hole, fold back on the notch then twist. It works perfectly for temporary usage.