\defaultfontfeatures[PennstanderMath-Bold]
{
  UprightFont  = PennstanderMath-Bold.otf,
  BoldFont     = PennstanderMath-Black.otf,
  %script-font  = PennstanderMath-Bold-script.otf,
  %sscript-font = PennstanderMath-Bold-sscript.otf
}