Diablo, 3/8" x 18" installer bit. Diablo's installer drill bits offer premium performance and superior life in wire installation projects. An ultra-sharp tip maximizes durability for fast, straight holes in clean wood or stacked lumber. Black oxide coated flutes prevent debris build-up for fast chip removal. The small hole in the flute makes feeding cables and wires effortless. The 3-flat shank provides extra stability by eliminating spinning in the drill chuck.