Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number GFBFST20BK found under Interrupterground Fault by Hubbell Ltd. The National Stock Number assigned to this part is 5925016979026, 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 GFBFST20BK.