Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 21-19742 PIECE 16 found under Key Machine by Treadwell Corporation. The National Stock Number assigned to this part is 5315011510966, and the Federal Supply Class is 5315 Nails Machine Keys And Pins. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 21-19742 PIECE 16.