VEVOR 4PCS Machinery Skate Dolly, 26455LBS/12T Industrial Machinery Mover, Heavy Duty Carbon Steel Machinery Moving Skate & 4 Carbon Steel Wheels and 360° Rotation Non-slip Cap for Warehouse, Factory

The weight refers to the total load capacity of 4 units, which is 12 tons.

While the product description doesn't mention anything about uneven surfaces, customers generally have positive things to say about the wheels. Customers consistently state the wheels allow for smooth movement. One review mentions the floor needs to be clean and smooth.

While the product description doesn't mention anything about replacement parts, customers generally have positive things to say about the product's quality. The quality of the wheel bearings and rotary plate seem fine for moderate use, according to customers.

The product description states it is constructed from carbon steel and has a surface spray coating process for wear and corrosion resistance. Customers agree with many noting its sturdy construction. One review mentions modifying it for added stability, but overall it seems well built for the intended purpose.

The product description states it has a 26455 lb load capacity. Customers agree with many noting its ability to move heavy machinery and equipment. One review mentions using it to move a 15,000 lb machine.