This part of ISO 11151 specifies requirements for laser components used from near-infrared to midinfrared, from wavelengths 2,1 μm to 15,0 μm, and facilitates the supply of spare parts - by specifying preferred dimensions and tolerances, thereby reducing the variety of types, - by standardizing the specifications and removing barriers to trade, and - by establishing an agreed designation for item orders. This part of ISO 11151 covers planar, plano-spherical, and spherical substrates, lenses, and optical components that are designed specifically as standardized optical components normally offered through a catalogue from suppliers and intended for use with lasers. This part of ISO 11151 includes component descriptions, materials employed, physical dimensions, and manufacturing tolerances (including surface finish, figure, and parallelism). Although most, but not all of these components will be coated (fully reflecting, partially reflecting, or anti-reflecting) before incorporation into the laser system, this part of ISO 11151 does not include recommendations for the specification of coatings.