The most hotly discussed digital refractometers are the Atago PAL-1, the Atago PAL-2, the Atago PAL-3, the Atago PAL-4, and the Atago PAL-RI. These refractometers are designed to measure the refractive index of a variety of liquids, including juices, beverages, and other solutions. They are highly accurate and easy to use, making them popular among professionals in the food and beverage industry.