Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 21988 found under Hose Assembly Nonme by Hardigg Industries Inc. The National Stock Number assigned to this part is 4720016101713, 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 21988.