Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 90-2020 found under Rule Multiple Foldi by Keuffel And Esser Co. The National Stock Number assigned to this part is 5210004698117, and the Federal Supply Class is 5210 Measuring Tools Craftsmens. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 90-2020.