Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number NK505-2R4 found under Screw Cap Socket He by Schaefer Corp. The National Stock Number assigned to this part is 5305008180517, 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 NK505-2R4.