Who's who? What's what?

First, a little vocabulary lesson. The wavy paper inside the corrugated board is called the corrugating medium. The flat sheets on the outside are called liners.

Liner paperboard can be a natural brown color, mottled white, or all white. Most is made with about 35 percent recycled fiber, but recycled content can be up to 100 percent.

There are standard sizes of flutes, the ridges in the corrugated medium. Some corrugated boards have small numbers of very large flutes; others have higher numbers of very small flutes. The use of the box determines which flute style is best.

A single liner, glued to corrugating medium, creates singleface corrugated board. This flexible material is sometimes used to cushion items such as light bulbs.

Corrugating medium glued between two flat liners forms a single wall corrugated board. Most of the boxes we see every day are made of this material, and in fact about 90 percent of corrugated board is single wall.

Adding another corrugating medium and a third flat liner creates a double wall corrugated board. Stronger than the single wall board, it's also heavier and more expensive. Furniture, appliances and products such as nails, meat, and bulk peanuts are packed in boxes made from double wall corrugated board.

There are also triple wall corrugated boards, big tough boards with three layers of corrugating medium and four flat liners, used for very large or very heavy products.