| Ex grade | ANSI/UL 1203 Size:1/2″, 3/4″ — Class I, Division 1, Groups A, B, C, D — Class II, Division 1, Groups E, F, G — Class III Size:1″, 1-1/4″, 1-1/2″, 2″ — Class I, Division 1, Groups C, D — Class II, Division 1, Groups E, F, G — Class III IEC 60079 Size:1/2″ ~ 4″ Ex db ⅡC Gb Ex tb ⅢC Db ATEX Size:1/2″ ~ 4″ Ⅱ 2G Ex db ⅡC Gb Ⅱ 2D Ex tb ⅢC Db |