The DM221 power supply, with a voltage of 6V, can be used with DC plugs of 6V 400MA, 6V 500MA, and 6V 800MA that have a size of 4.0 * 1.7MM.
Power supply for VTech baby monitors DM221, DM221-2, DM223, DM251 (both parent and baby units), and DM111, DM112, DM222, DM271 (parent unit only).