Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number CRR 50 THRU 52 found under Parts Kit Pressure by Circor Aerospace Inc. The National Stock Number assigned to this part is 4820010351455, 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 CRR 50 THRU 52.