In addition to many sizes, manufacturers offer a wide selection of styles and finishes. It's not unusual for a single company to offer three different cabinet lines, distinguished by price and quality, and a dozen different door styles in each line.
Styles typically range from contemporary laminates to traditional hardwoods like oak and cherry. Most companies also offer several finishes on natural woods.
One way dealers can offer a broad selection without carrying an unwieldy inventory is to utilize a "box and door" program. They carry standard-sized cabinet "boxes" and a wide range of door and drawer fronts to fit the boxes.