Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 4022-939-4321 found under Window Observation by Chart Sequal Technologies Inc. The National Stock Number assigned to this part is 9330013413337, and the Federal Supply Class is 9330 Plastics Fabricated Materials. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 4022-939-4321.