Comparison : Item # WMU045-4000, 4.5 Volts (V) Output Voltage (DC) and Positive Polarity Center Wall Plug-In Power Transformer
Item # WMU045-4000-R, 4.5 Volts (V) Output Voltage (DC) and Negative Polarity Center Wall Plug-In Power Transformer
Item # WMU045-4000-13, 4.5 Volts (V) Output Voltage (DC) and Positive Polarity Center Wall Plug-In Power Transformer
Item # WMU045-4000-R13, 4.5 Volts (V) Output Voltage (DC) and Negative Polarity Center Wall Plug-In Power Transformer
Item # WMU050-4000, 5.0 Volts (V) Output Voltage (DC) and Positive Polarity Center Wall Plug-In Power Transformer