Hardened nail specifically designed for fixing to masonry and concrete blocks. Countersunk head for flush fit 35 sharp point for easy penetration Hardened carbon steel for extra strength Bright zinc plated for internal use" Shank Dia. mm: 2.50 Length mm: 35 Material: Hardened Carbon Steel Colour: N/A Head Dia. mm: N/A Timco Masonry Nails - Zinc (Size 2.5 x 35 - 50 Pieces) in Silver