This isone of the most commonly used classifiers for gold prospecting. This heavy duty plastic classifier from Garrett is light, functional and very affordable. It fits nicely in a 5 gallon bucket or gold pan, and nests with most popular 14" pans on the market for easy packing to the stream and convenient storage. The holes are 1/2" square.
Garrett 1/2" Classifier (fit's 14" pans)