12 V DC Mains adaptor. 2.1 mm centre positive plug.

• AC ADAPTOR, 12 V, 0.5A REGULATED
• Output Current:0.5 A
• Output Voltage:12 V
• Power Rating:7.5 W
• External Width:50 mm
• External Depth:26.5 mm
• Approval Bodies:CE, CB, RoHS
• Efficiency:63%
• Height:64 mm
• Max Supply Frequency:63 Hz
• Max Supply Voltage AC:264 V
• Min Supply Frequency:47 Hz
• Min Supply Voltage AC:90 V
• No. of Outputs:1
• Output Type:2.1mm DC Plug
• Power Supply Type:Plug-In External
• Weight:0.13 kg

This is a 12 V mains adaptor for LCD monitors etc.