Concrete nails are used to fasten materials, typically wood, to concrete, stone, brick, or other masonry structures by driving them into the hard surface. Made from hardened steel, they are designed with a flat head, a diamond point, and often flutes or grooves on the shank to improve their ability to penetrate and grip dense materials. Common applications include attaching furring strips, wood framing, and baseboards to concrete walls in both building and home improvement projects.