Freud 7016R 20mm Carbide Tipped Boring Bit Countersink 82 Degree RH 7016R Strong Bolt 2 Wedge Anchor Two hour fire resistant rating for 2x4 Two hour fire resistant rating for 2x4 or thicker walls provides confidence that the connection meets fire separation requirements on both sides of the wall making this wedge anchor a dependable choice when corrosion resistance and structural holding strength are both required in outdoor or exposed conditions countersink angle the correct geometry for flat head fastener seating across a broad range of composition materials Freud Carbide Tipped Boring Bit Countersinks are precision engineered accessories designed for high demand industrial woodworking operations