Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number SER550-5N2 found under Gage Stroke Project by Bell And Howell Phillipsburg Co. The National Stock Number assigned to this part is 5220005178618, 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 SER550-5N2.