Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number B4 50 203 12 found under Handle Bow by Southco Inc. The National Stock Number assigned to this part is 5340013921351, and the Federal Supply Class is 5340 Hardware Commercial. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like B4 50 203 12.