Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number MC-025-B SHEET 5 ITEM 27 found under O Ring by Newmans Inc. The National Stock Number assigned to this part is 5331013161335, 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 MC-025-B SHEET 5 ITEM 27.