Please note that you need to note the power when purchasing, 2000W/2500W/3000W/3500W? If there is no note, the default power is 3000W. Note: for this one motor, the 12 inch size is the motor with tyre size. Not the tyre, only this one hub is not 12 inch. Hope you can check the size before you order it. Not the tyre, this one hub only is not have 12 inch. 60V 72V is double out line. (the double out line have the picture shows, it is for big power). The double out lines need all connect with one controller. You can leave a message about how much power you need. If there is no message, we will send it randomly. 112 inch Hub Motor. This is double out line.