1950s-era Baby's Twin Turtle Bib-Holder.  These plastic turtles clip onto any bib or cloth to keep in place without tying a bib the conventional way.  I replaced a well-worn strap with a new cotton twill strap.  I made the strap much longer to allow for adjustments.  It can easily be trimmed down to a smaller size if desired.  Cotton twill is available at most fabric stores or online to replace the strap when worn out.