This machine separates pre-cleaned products, or products that do not require cleaning, into five different sizes or removes broken pieces from the product. The four-deck grading machine is generally placed under the photosorter (color sorting) machine and used for final control. It can optionally be manufactured as fixed or mobile (wheeled).

The four-deck grading machine separates the product only by size and is not used for cleaning purposes.

The four-deck grading machine differs from the three-deck grading machine by having one additional screening deck.

The four-deck grading machine separates the product into five different sizes and removes broken pieces from the product.