All part numbers will follow this format: AN###. To further distinguish between the part numbers, you'll notice that a dash ("-") has been added, followed by some specific variation of more numbers. If there is an "A" after the dash, the part is cadmium plated, Type I, Class 3, with a drilled head. If there is NOT an "A" after the dash, the part is Cadmium plated, Type I. AN500 (coarse thread) and AN501 (fine thread) slotted fillister head screws are fabricated from carbon steel. Tensile strength 55,000 PSI AN502 (fine thread) and AN503 (coarse thread) drilled head, slotted fillister head screws are fabricated from steel meeting specification MIL-S-6050. Tensile strength 125,000 PSI. Cadmium plated, Type I Class 3. |