The heavy duty roller skid (also known as a heavy object transporter, a crawler transport tank, and a gravity trolley) is a heavy-duty transport tool used for short-distance/long-distance heavy-duty horizontal shifting. It is composed of a high-strength alloy steel frame, high-loading rollers/rollers, and chain guide rails. The load capacity of a single unit is usually 5 tons to 500 tons, and a combination of multiple units can carry thousands of tons of weight.