Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 1522E28-20 AND 1520E21-30 found under O Ring by Westinghouse Electric Corp. The National Stock Number assigned to this part is 5331013593054, and the Federal Supply Class is . Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 1522E28-20 AND 1520E21-30.