heater tube Grade: 304.321.316L.309S.310S O.D:3mm-12mm ... .25-1.5mm Appliance:Electronics,hardware,ect ASTM A554,A269 heater tubeFeatures: 1) Production Standard :ASTM A269;ASTM A554,2) Material ... tolerance,7),hardness:high,middle,low.8),cuting without burr. heater tube