Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number S 1 4-20 X 3 8 found under Screw Cap Socket Head by A P M Hexseal Corporation. The National Stock Number assigned to this part is 5305010683447, 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 S 1 4-20 X 3 8.