The secret to capturing fine gold is classify, classify, classify. Pioneer's interlocking and stackable classifying screens come in different sizes so you can mix and match the right sizes for the material you're working with.
The screens also come with an optional top lid and bottom tray so you can shake your material through the screens or you may use without the lids.
Classifiers are sold individually. Mesh size is determined by how many squares per linear inch. For example, a 20 mesh sieve would have 20 squares per running inch or hole size of 1/20".