Regular Slotted Box - 2 x 2 x 9

Also called shipping boxes, RSB is the most commonly used box.

All flaps have the same length, and the two outer flaps (normally
the lengthwise flaps) are one-half the container’s width so that
they meet at the center of the box when folded. If the product
requires a flat, even bottom surface, or the protection of two full
layers, a fill-in pad can be placed between the two inner flaps.
This is a highly efficient design for many applications. There is
very little manufacturing waste. The RSC can be used for most
products and is the most common box style.