Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 13-00031-004 found under Crystal Unit Quartz by Monitor Products Co Inc. The National Stock Number assigned to this part is 5955009175063, and the Federal Supply Class is 5955 Oscillators And Piezoelectric Crystals. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 13-00031-004.