MKT Steel Conset Masonry Screw Anchor, Hex Washer Head Faced, 1/4" Diameter x 3-1/4" Length (Box of 100) Commonly known as "Tapcon" High strength steel for use in all types of solid and hollow masonry, wood and stone Fluorocarbon coating offers high resistance to corrosion; costing withstands 1000 hour salt spray test Cuts its own threads; hex head version offers 2 drive methods Fast, easy installation; drill bit included in each box