Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 21-CASTERS-3.5 found under Caster Swivel by A P T Radar Systems Ltd. The National Stock Number assigned to this part is 5340014920537, and the Federal Supply Class is 5340 Hardware Commercial. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 21-CASTERS-3.5.