1. porcelain insulator 2. type test 3. grey or brown 4. According to IEC, GB, ANSI, BS, JIS, AS,DIN standard Pin type insulator, post type, Disk type and all kinds of ceramic insulators use on transformer, fuse cutout, surge arrester.Surface glaze of insulator available color of white, gray, blue, brownAccording to IEC, GB, ANSI, BS, JIS, AS,DIN. ceramic insulator/ porcelain insulator- 57-1 57-2