CPC Subgroup
G09B 23/22 for optics
Full Title
Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes (in the nature of toys A63H) > for physics > for optics
G09B 23/22 Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes (in the nature of toys A63H) > for physics > for optics