AC powered with 100’ power cord. Comes with a receptacle that attaches to the side at the front of the trailer that acts as the pivot point. The AC-5 unit is rated to move up to a 4,250 pound trailer. CRITICAL FACTORS: MAXIMUM TRACTION IS KEY Since 85% to 93% of your trailer’s weight is typically centered over its axles, dolly traction is of key importance. That is why we utilize 4-ply diamond stud tires and use more of them than anyone else. The more tires you have, the more traction you attain. Moreover, since our dollies generally attach further underneath most trailers, more weight is put onto them, giving you even more critical traction. Our AC dollies operate in forward and reverse.