select1

The default styling of the options in a select1 control is to look like a radio button:

xf\:select1 .pc-selected
{
  background-image: url(radio-selected.png);
}

xf\:select1 .pc-deselected
{
  background-image: url(radio-deselected.png);
}

The images used are:

radio-selected.png:   

radio-deselected.png: