Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 53-87211-4 found under Window Observation by Monogram Aerospace Fasteners Inc. The National Stock Number assigned to this part is 9330000563315, 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 53-87211-4.