... box ,surface box sizes: 3"x3" ,3"x6"20mm/ 25mm knockouts color : white Square stamping conduit 1) name:switch box, 2 gang box , 1 gang box ... ,flushing box,surface box2) sizes: 3"x3",3"x6"box, 20mm/25mm ... ,electrical equipment , components12)PVC 2 gang box are used as surface mounting ,control box , switch box or general service box plastic surface box