Most rainbow pencil boxes are made from plastic or EVA (ethylene vinyl acetate); some options are metal.
Common closure types include zippers, snap-top lids, clasps, and elastic closures.
Typical dimensions are about 7.5–8.5 inches wide and 2–2.5 inches deep; some designs list capacity for up to about 60 pens and pencils.
Common interior features are roomy compartments, mesh pockets, elastic pencil bands, and soft anti-scratch linings to protect contents.
A few metal supply boxes include a key lock and reinforced corners to secure small valuables in addition to school supplies.
