Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number MA-216993 REV 0 ITEM 4 found under Retainer Seal by Zurn Industries Inc. The National Stock Number assigned to this part is 5330014108437, and the Federal Supply Class is 5330 Packing And Gasket Materials. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like MA-216993 REV 0 ITEM 4.