Singlewall corrugated is the most common material used in corrugated boxes. It consists of one layer of fluting between two linerboards and is available in a wide range of strengths, typically from 23 ECT to 44 ECT. Singlewall works well for many packaging applications but may not be ideal for shipping heavier products.

Doublewall corrugated consists of two layers of fluting between three linerboards, most commonly combining B and C flutes. This structure provides greater strength and cushioning than singlewall and is well suited for shipping heavier items or when additional stacking strength is required. Doublewall is typically available in 48 ECT to 71 ECT.

Triplewall corrugated consists of three layers of fluting between four linerboards, creating an extremely strong board structure. Often used as a corrugated alternative to wooden crates, it is designed for shipping very heavy or bulky products and is typically available in strengths of 90 ECT and higher.

In corrugated packaging, the flute is the wavy layer of paper between the flat linerboards. The flute structure gives corrugated boxes their strength, cushioning, and rigidity. Different flute sizes provide different performance characteristics.

The original corrugated flute and one of the thickest. Provides excellent cushioning and stacking strength, often used when extra protection is needed.

A thinner flute with more flutes per foot. Provides a stiff surface for printing and die cutting, making it common for pads, partitions, trays, and retail packaging.

The most widely used flute type. Offers a strong balance of cushioning, stacking strength, and printability, making it common for standard shipping cartons.

A very thin flute with a smooth surface for high-quality printing. Often used for retail packaging and smaller boxes where a thinner profile is desired.

An ultra-thin flute used for high-end retail packaging and premium graphics.