Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number R5400-520 found under Tubing Nonmetallic by Resistoflex Corp Southwestern Div. The National Stock Number assigned to this part is 4720000593392, 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 R5400-520.