Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number AG 16 S1 found under Block Step Machinists by Ls Starrett Company The. The National Stock Number assigned to this part is 5220013790470, 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 AG 16 S1.