Duplex nail, once called a scaffold nail, is now known as a double-headed nail. As the name suggests, its most distinctive feature is a double-headed head. The unique configuration is designed to for easy removal when a temporary construction projects finished. Workers can drive the nail until the lower head is flush with the material and extract the upper head with pull bar or the reverse end of a claw hammer. Duplex nails are ideally for temporary structures, such as braces, scaffolding, formwork for pouring concrete or attaching temporary cleats during roofing work.