This 3-piece set of Premium Classifier Screens is made of durable plastic with 304 Stainless Steel wire. These classifiers fit onto a 5 gallon bucket, and are stack-able which let's you classify 3 different sizes at a time. These classifying pans work fantastic for Gold Panning, Sluicing, Dry Washing, or for separating different size gems or rocks! Each measures about 13-1/4 inches in diameter on top and 11 inches in diameter on the bottom. The wire thickness is 1.4mm on the 1/2" classifier, 0.45mm on the 1/12" classifier, and 0.35mm on the 1/20" classifier.