Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number BS1-5A50-543NBR found under by R F Technologies Inc. The National Stock Number assigned to this part is 4820016824789, and the Federal Supply Class is 4820 Valves Nonpowered. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like BS1-5A50-543NBR.