Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 161D8321 found under Seat Valve by Kapl Inc. The National Stock Number assigned to this part is 4820013603744, and the Federal Supply Class is 4820 Valves Nonpowered. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 161D8321.