Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number D21489 found under Hose Air Duct by Rheem Mfg Co. The National Stock Number assigned to this part is 4720001041984, and the Federal Supply Class is 4720 Hose And Flexible Tubing. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like D21489.