Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number AY503F21A3 found under Synchro Transmitter by Honeywell Aerospace. The National Stock Number assigned to this part is 5990008592932, and the Federal Supply Class is 5990 Synchros And Resolvers. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like AY503F21A3.