... .0.15~2.5mm*8~650mm 4.round, slit Blue Tempered spring steel strip for rolling shutter doorHeat treatment is ... : DC01, DC03, DC04, DC05, DC06 according to EN Standards CD, DQ, DQSK according to ASTM Standards Enameling Grades: DC01EK, DC04EK ... or EK2, EK4Finishes: Nature, Polished bright, grey blue, polished blue, yellowEdge: Mill, Slit, Round, sheared/millTensile strength: 1405-1577 ...