Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 18520 found under Knife Pocket by Stanley Proto Industrial Tools. The National Stock Number assigned to this part is 5110013999326, and the Federal Supply Class is 5110 Hand Tools Edged Nonpowered. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 18520.