Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number NO PRIMARY REF 12 189 4165 found under Circuit Breaker by This Ncage Is Used To Inform That. The National Stock Number assigned to this part is 5925121894165, and the Federal Supply Class is 5925 Circuit Breakers. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like NO PRIMARY REF 12 189 4165.