a lens that may be raised from its usual down position as needed
US Department of Labor, Eye and Face Protection eTool: Glossary, Occupational Safety & Health Administration OSHA, Washington, D.C., USA 2010. https://www.osha.gov/SLTC/etools/eyeandface/glossa ry.html, (OSHA/ Eye and Face Prot - Amer) {622}
