Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number XB1019FW35-4C found under Regulator Thermostatic Temperatu by Progress Supplyinc. The National Stock Number assigned to this part is 4820000661288, 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 XB1019FW35-4C.