Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number D-6433 ITEM 4 found under Valve Compressor by Wartsila Water Systems Limited. The National Stock Number assigned to this part is 4820012592066, 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 D-6433 ITEM 4.