Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number WST-137S16 found under Ringretaining by Smalley Steel Ring Co. The National Stock Number assigned to this part is 5325016969344, 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 WST-137S16.