Parent chapter HS 90 - Optical, photographic, measuring, checking, precision and medical instruments Subheadings in this heading HS 902300Instruments, apparatus and models, designed for demonstrational purposes (for example, in education or exhibitions), unsuitable for other uses. Final HS codes HS 90230000Instruments, apparatus and models, designed for demonstrational purposes (for example, in education or exhibitions), unsuitable for other uses.