Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 537B21-11 found under Latch Snapslide Fastener by Cardwell Condenser Corp. The National Stock Number assigned to this part is 5325003062357, and the Federal Supply Class is 5325 Fastening Devices. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 537B21-11.