Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 03.640.172 found under Valve Brake Proportioning And Wa by Mico Inc. The National Stock Number assigned to this part is 2530013652959, and the Federal Supply Class is 2530 Vehicular Brake Steering Axle Wheel And Track Components. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 03.640.172.