Indicates the kind of product that this is a variant of. In the case of <a class="localLink" href="/ProductModel">ProductModel</a>, this is a pointer (from a ProductModel) to a base product from which this product is a variant. It is safe to infer that the variant inherits all product features from the base model, unless defined locally. This is not transitive. In the case of a <a class="localLink" href="/ProductGroup">ProductGroup</a>, the group description also serves as a template, representing a set of Products that vary on explicitly defined, specific dimensions only (so it defines both a set of variants, as well as which values distinguish amongst those variants). When used with <a class="localLink" href="/ProductGroup">ProductGroup</a>, this property can apply to any <a class="localLink" href="/Product">Product</a> included in the group.