Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 11989 found under Window Observation by Kemp C M Mfg Co. The National Stock Number assigned to this part is 9340001368790, and the Federal Supply Class is 9340 Glass Fabricated Materials. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 11989.