Mono-Wheel
The Mono-Wheel trailer appears to be the Marville Dwyer Trailer Division venture into the single wheel trailer market. The Marville Dwyer Trailer Division is better known for their tear drop trailers. Possibly related is this excerpt from “Iron Age” Volume 105 – “The Dwyer Mfg. Co., Los Angeles has been incorporated with a capitol stock of $50,000 by C. Marville and M. A. Dwyer, a R. M. Gilson, to manufacture automobile parts and accessory equipment. Only 1 Mono-Wheel has been discovered.