Comparison : Item # 4323, 15" Display FM Approved Class I, Division 2 Hazardous Area PC
Item # 4326, 19" Display FM Approved Class I, Division 2 Hazardous Area PC
Item # 4329, 21.5" Display FM Approved Class I, Division 2 Hazardous Area PC
Item # 4523KP, 15" Display Class I, Division 2, FM Approved Industrial Hazardous Area PC
Item # 4526KP, 19" Display Class I, Division 2, FM Approved Industrial Hazardous Area PC