Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 55-197 found under Tube Gauge Vacuum by Teledyne Instruments Inc. The National Stock Number assigned to this part is 4710004995059, and the Federal Supply Class is 4710 Pipe Tube And Rigid Tubing. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 55-197.