Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number OP-2B found under Optical Flat by Van Keuren. The National Stock Number assigned to this part is 5210011299262, 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 OP-2B.