This document defines and classifies properties of passive showcases for the safe and secure display of cultural heritage objects for better preservation. It applies to most uses of the showcase: showcases for so called permanent or temporary exhibitions, historical or modular showcases, showcases in uncontrolled ambient environment, etc. Aspects of active showcases (those using electricity to directly condition their microclimates) and anoxic showcases (those containing inert atmospheres instead of air) are mentioned in this document, but their properties are not defined, nor classified.