The term 2D refers to the nail’s gauge and length, specifically 2 penny (2d) which correlates to a length of about 1 inch. Finish nails are characterized by their small, slender bodies and a smaller, distinctive head. Unlike common nails which are thicker and have a larger head, finish nails are designed to be subtle, allowing them to be driven into the wood without leaving a prominent mark. This feature is particularly advantageous for projects where aesthetics are crucial, such as cabinetry, millwork, and trim applications.