Abstract: Optical apparatuses selectively used under scotopic and mesopic vision conditions. The optical apparatuses include a lens having a low-light suitable shape effective to focus light in the eye under scotopic and mesopic vision conditions. The low-light suitable shape is distinct from a bright-light suitable shape effective to focus light in the eye under photopic vision conditions. In some instances, the optical apparatuses include a spectral filter.

Abstract: This invention relates to the method for producing a coded reference key for use in the locksmithing trade. The method comprises cutting a key blank at a first coded depth and at a first shank position, to create a partial silhouette of a reference key. Upon cutting a number of such partial reference key silhouettes at a number of positions and common depths, a set of partial reference key silhouettes can be created. When a locksmith is required to reproduce a reference key which has certain depth cuts at certain positions, he merely assembles the appropriate pre-cut partial reference keys, thereby creating the required complete silhouette. This complete reference key silhouette may then be duplicated by using a standard reference key duplicating machine.