Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number ST 431 found under Gage by Textron Lycoming Inc. The National Stock Number assigned to this part is 5220013628581, and the Federal Supply Class is 5220 Inspection Gages And Precision Layout Tools. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like ST 431.