I thought it was some sorta new golf-club at first.
Here's the text of the ebay ad.
How would you use this on a bike, dare I ask ?
This is a brand new single phase (1 ph) converter for AC operation of DC motors. It converts AC current to DC so you can run low cost treadmill, Ametek and other DC motors for compressors, pumps ECT. Convert any voltage from 0 volts up to 180V AC to DC current. For instance convert 48V AC to 48V DC, 24V AC to 24V DC, 120 AC to 120 DC and 180V AC to 180V DC. Any voltage can be converted to its corresponding DC voltage up to 400V DC. Its maximum ampere rating is 35 Amp at any voltage up to 400V. This converter will not alter voltage, it changes current from AC current (Amps) to DC current only. DC wire are connected to the tabs with the + and - signs next to it as shown in the picture. AC wire can be wired with no difference to which AC tab each AC wire is connect to. The two pictures illustrate hookup of converter, the second item in the picture is a heatsink which should be attached as shown in the second picture. The heat sink keeps the device cool. The red (wire) is connected to the positive DC tab and the green lead (wire) to the negative tab. DC tabs has + sign for positive DC wire and a – sign for negative DC wire. The AC wire which is all black, wire leads connection is interchangeable on the converter tabs as shown. When working with electricity proper precautions must be taken.