Ideal for use any Propeller board that requires 7.5 V.D.C. from a 2.1 mm centre positive plug.

• AC ADAPTOR, regulated 7.5 VDC
• Output Current:1 A
• Output Voltage:7.5 V
• Output Type:2.1mm Plug
• Power Rating:7.5 W
• External Width:50 mm
• External Depth:26.5 mm
• Height:64 mm
• Weight:0.13 kg
• Approval Bodies:CE, CB, RoHS
• Efficiency: 63%

You may have a suitable adaptor already, or can find a "universal" adaptor on ebay or in a shop near you. This one has a fixed 2.1 mm plug, it's compact and good quality. There is a 12 V version for LCD monitors etc.