Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number M3900004 found under Hose Assembly Nonmetallic by Biach Industries Inc. The National Stock Number assigned to this part is 4720013398527, 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 M3900004.