In the HGS Stereochemistry Molecular Models, the bonds and atom unite with each other; namely the bonds and atom are not separable. Therefore, it is handy to construct various molecular models. This is the basic set of the stereochemistry molecular models, and hence is useful for constructing simple organic compounds such as alkanes, alkenes, alkynes, aromatics, alcohols, ketones, esters, amines, amides etc. The HGS Stereochemistry Model is also useful for demonstrating the ring flip of cyclohexane ring; namely, the chair form undergoes the ring flip to form the other chair form, via the intermediate of boat form, because the partial rotation around the C-C bond is smooth during the conformational changes.