5/16"-9 x 1-1/2" Grade A Zinc Finish Hex Head Lag Screw / FASTENER LENGTH: 1.500 INCHES NOMINAL HEAD STYLE: C1 HEXAGON HEAD HEIGHT: 0.195 INCHES MINIMUM AND 0.235 INCHES MAXIMUM WIDTH BETWEEN FLATS: 0.484 INCHES MINIMUM AND 0.500 INCHES MAXIMUM SHOULDER DIAMETER: 0.298 INCHES MINIMUM AND 0.324 INCHES MAXIMUM SHOULDER LENGTH: 0.125 INCHES MINIMUM MINIMUM TENSILE STRENGTH: 55000 POUNDS PER SQUARE INCH HARDNESS RATING: 60.0 ROCKWELL B MINIMUM OVERALL NONMACHINE THREAD STYLE: A13 GIMLET POINT (TYPE A, AB OR BA) NONMACHINE NOMINAL THREAD DIAMETER: 0.312 INCHES SHOULDER SHAPE: ROUND FIRST SHOULDER SPECIAL FEATURES: THREADS: 9 THREADS PER INCH MATERIAL: STEEL OVERALL SURFACE TREATMENT: ZINC OVERALL SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: ASTM-B633 ASSN STD SINGLE TREATMENT RESPONSE OVERALL