Product standard:ASTM A269,A249,EN,TP304,321,316L.... Appliance:electric heater,heater elements O.D.:from 6mm to 23mm Features: 1) Production Standard :ASTM A269;Enterprise Standard2) Material of commonly used stainless steel:TP304,TP321,TP316L,TP309S,TP310;Material of other stainless steel:202,302,INCOL800,840,8253) Product applications and applicable field:all kinds of metal tubular heaters, ...