The Air Compressor category is divided into four subcategories: Accessories, Electric, Gasoline and Diesel. When a category with subdivisions is selected, the user sees the defined subcategories. He clicks on one of the subcategories to see the types associated with the subcategories. This allows a user of your website to more narrowly identify items of interest. RentControl only supports two levels of organization (category and type), but for the web export, you can further divide inventory into supercategories and subcategories. (See Tables for an example that uses a supercategory.)