Washable 4-in-1 Stamp Pad Primary ColorsThis washable 4-in-1 primary color stamp pad is perfect for rubber stamps and for decorating with child hand prints and mementos. Aids students with counting, sorting, grouping, connecting, and comparing items. Features four primary colors: Red, Green, Yellow, and Blue. The dye-based, unscented ink is completely child safe, non-toxic, acid-free, and archival quality. Measures 3" x 1 1/2". Conforms to ASTM D-4236.