Box nails are similar to common nails but have a slimmer shank and have less holding power. Box nail is used on lighter pieces of wood and on boxes, and also used for installing clapboard siding. They are especially good for this application because the thinner nail tends to crack the siding less. The nail also has a slightly larger head, which helps the nail keep the siding in place, even when the sun and temperature might cause the wood to shrink or swell somewhat.

Bright box nails

Box nails are most often used with a galvanized coating on them, so that they will stand up to the weather better.