This series of pushbutton switches are used for automation and signals in control circuits below AC 660V, DC 440V with frequencies of 50Hz or 60Hz Model No.: XB2-(BD21, ED21) 1) Diameter of installation bore: 22mm 2) The front colors: Black 3) Many types available: Pilot lamps, pushbuttons, illuminated pushbuttons, selector switches, and key lock switches 4) Inner packing: 20pcs/box Outer packing: Carton dimensions: 35 x 30 x 25.5cm Model No.: XB2-(BJ33, EJ21) 1). The difference from other knob lies in its long-hand handle. 2) other features are same as products shown above Model No.: XB2-(BG21, EG21) 1) this kind of pushbutton has a key on its head 2) other features are same as products shown above