Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number ASME B18.2.1 found under Screw Cap Hexagon Head by American Society Of Mechanical. The National Stock Number assigned to this part is 5305000712507, and the Federal Supply Class is 5305 Screws. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like ASME B18.2.1.