Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 18563 found under Valve Indicator by Rolls Royce Marine A S Dep. The National Stock Number assigned to this part is 4820013026872, 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 18563.