The Travers retractor is usually a self-retaining retractor, with small finishes for use in maintaining superficial wounds open To gauge the necessity for supplies/equipment and health workforce requirements during the COVID-19 pandemic, WHO has created a suite of complimentary surge calculators -- one for supplies and two for health workforce. https://rowanjgcum.rimmablog.com/31697150/helping-the-others-realize-the-advantages-of-medical-supplies