Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number AN-1.25-125B-A ITEM 4 found under O Ring by Core Industries Inc. The National Stock Number assigned to this part is 5331012550137, 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 AN-1.25-125B-A ITEM 4.