Pre-Expanded Anchor Anchor Diameter 1/4 in Overall Length 1 1/2 in Anchor Material Steel Finish Zinc Plated Head Type Flat Head Height 0.140625 in Head Diameter 0.5 in Drill Bit Size 1/4 in Minimum Installation Depth 1 1/8 in Drive Pin Anchor Type Steel Drive Anchors Compatible Material Concrete Wood Material Grade/Class Heat Treated Removable Permanent System of Measurement Inch Manufacturer Location Globally Sourced Features Tamperproof