Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number RHD-18-L found under by Gs Hydro U S Inc. The National Stock Number assigned to this part is 4820016827541, 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 RHD-18-L.