Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 4012 found under Arrester Lightning by Guest Co Inc The. The National Stock Number assigned to this part is 5920014966966, and the Federal Supply Class is 5920 Fuses Arresters Absorbers And Protector. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 4012.