The Kerian Sizer uses a single set of rotating rollers that gradually separate as they gently carry the potatoes forward. The potatoes are thus sized accurately and consistently by diameter. The roller spacing is set by a pair of precisely machined spiral drives with increasing pitch along the length of the sizer. The extreme accuracy of the roller spacing allows precise separation of both long and round potatoes by minimum diameter, with quick adjustment possible by sliding a divider separating sizes. The Kerian Sizer comes in 13 standard models, offering each grower a maximum value and a machine perfectly suited to their capacity and number of sizes.