all kinds of switch box ,surface box sizes: 3"x3" ,3"x6"20mm/ 25mm ... , 2 gang box , 1 gang box,flushing box,surface box2) sizes: 3"x3",3"x6"box, 20mm/ ... order are available6)2 gang box are used as surface mounting control box , junction box or general service ... Installation during the process of construction ,electrical equipment , components12)PVC 2 gang box are used as surface mounting ,control box ...