Twist Locks 2 : A set of four twistable bayonet type shear keys used as part of a spreader to pick up a container or as part of a chassis to secure the containers
US Department of Transportation, Maritime Administration, Glossary of Shipping Terms, Washington, DC, USA 2008. http://www.marad.dot.gov/documents/Glossary_final. pdf, (Mrtm - Amer) {572}