THESE CLASS 10.9 HEX HEAD CAP SCREWS ARE HEAT-TREATED CARBON AND BORON FASTENERS USED IN HEAVY-DUTY APPLICATIONS LIKE JOINING AUTOMOTIVE SUSPENSIONS, ATTACHING PLUMBING VALVES, AND BOLTING FORGED IRON PIECES TOGETHER. THESE SCREWS ARE SOLD IN BLACK OXIDE, BLUE PHOSPHATE AND ZINC YELLOW FINISHES AND HAVE HIGH-TENSILE STRENGTH AND WEAR RESISTANCE FOR LONG-TERM DURABILITY. BLACK OXIDE SCREWS ARE CORROSION RESISTANT IN DRY ENVIRONMENTS AND ZINC YELLOW SCREWS RESIST CORROSION IN WET ENVIRONMENTS. BLUE PHOSPHATE-DYED SCREWS HELP DISTINGUISH METRIC SCREWS FROM STANDARD FRACTIONAL FASTENERS.
