E-flute
A thin, fine corrugated material (~1.5 mm thick) used in mailer and retail boxes for a clean print surface with light cushioning.
Flute refers to the wavy paper core sandwiched between two flat liners in corrugated board. E-flute has ~90 flutes per linear foot, making it the second-finest corrugated grade in common use (only F-flute is thinner). The result is a board that's rigid enough to protect light-to-medium-weight goods, thin enough to die-cut crisp folds, and smooth enough to take high-resolution digital or offset print without the corrugation pattern telegraphing through.
E-flute is the default choice for branded DTC mailer boxes — the unboxing experience needs the print to look like a retail package, not a shipping carton. Use B- or C-flute when you need more crush protection, or double-wall when shipping fragile heavy goods.
Related terms
- B-fluteA medium-weight corrugated grade (~3 mm thick) that adds real crush resistance while still printing cleanly — common for shipping mailers.
- DielineThe flat, two-dimensional template that defines exactly how a piece of packaging is cut, scored, and folded before it becomes a box.
- EmbossingA finishing technique that raises a portion of the printed surface using paired dies, creating a tactile relief without ink.
- FSC certificationA Forest Stewardship Council audit that traces paperboard back to forests managed for biodiversity, worker rights, and indigenous land use.