Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 508-4-28203 found under Panel Voltage Selec by Zarlink Semiconductor. The National Stock Number assigned to this part is 6110999545208, and the Federal Supply Class is 6110 Electrical Control Equipment. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 508-4-28203.