Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 57-001 ASSY NB01620AE 6IN found under Valve Check by Pima Valveinc. The National Stock Number assigned to this part is 4820015004889, 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 57-001 ASSY NB01620AE 6IN.