Hardened steel, diamond point Designed for quick, secure fastening for a variety of jobs in poured concrete, brick and cinder block/masonry Diamond point provides self-threading, maximum holding power for fastening conduit clips, furring strips, junction boxes, expansion joints, wall partitions/insulation, stud track, window/door frames, duct strap, gutters, joist hangers, shelves, signs Blue corrosion coating 1/4 in. diameter x 2-1/4 in. length