Attributes . The optional attachable mechanical stage measures 112mm(X) x 72mm(Y). It has ergonomically positioned right-handed coaxial drop down controls. It also accepts the following optional accessory plates: 35mm, 55mm, 65mm, Petri Dish Holders, 96-well Terasaki Plate Holder, 1" X 3" glass slide holder, Hemacytometer holder. . Names