Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number CAT 18.33.31-A found under Regulator Thermosta by Clorius Controls A S. The National Stock Number assigned to this part is 4820222693385, 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 CAT 18.33.31-A.