SOCKET HEAD CAP SCREWS ARE IDEAL FOR PRECISION WORK WITH CLOSE TOLERANCES AND APPLICATIONS NEEDING A WELL TOOLED APPEARANCE. SOCKET HEAD CAP SCREWS SUPPLY GREATER TENSILE STRENGTH THAN EQUIVALENT HEX HEAD CAPS SCREWS, WHILE REQUIRING LESS SURFACE AREA TO COUNTERBORE. THERMAL BLACK OXIDE FINISH FEATURES A STANDARD HEAT TREATMENT FINISH WHICH INCLUDES LIGHT DRYING OIL; CHEMICAL BLACK OXIDE IS A CHEMICAL TREATMENT PLUS RUST WITH NO DRYING OIL.