HEADLOCK(R) H-D FLATHEAD FASTENER - No pre-drilling flathead screw fasteners ~ Faster easier stronger than 3/8" lag screws ~ Stronger design shear factor than 3/8" lags ~ Wafer head gives increased pull through strength ~ Spider Drive(TM) offers highest level of bit - ~ engagement and drivability ~ Sharp gimlet point installs fast in wood & OSB ~ Guaranteed corrosion resistance - ACQ approved