Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 21187-00316 found under Lockspring Turnlock Fastener by Selex Es Ltd. The National Stock Number assigned to this part is 5325003558963, 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 21187-00316.