1,approved by SGS used for high density heating elements 2,it can be OEM ... .9%MgO powder MgO tube1,approved by SGS used for high density heating elements2,it can be OEM3,material:99 ... ,appearance:with white color,smooth and vertical7, with High withstanding pressure,best insulating property,long life8.our standard size:(OD ... cables,the usage temperature can be 1600degreesC mgo tube for cartridge heater