Well, that doesn't look like one to me. But if it was, it was bought in addition to. The welders come with the roller installed.

What you said doesn't have any bearing on our company...or our factory and it's practices. The units have to meet our specifications and they are listed and spelled out as the supplier and the description as they must continue to meet ETL and they have surprise inspections. The aspects of the machine not only have the manufacturer and part number listed in detail, but if they deviate from it, then it must be retested at significant expense. If you'd just spend some time on here, researching it before you pontificate, you'd see detailed documentation of our factory, production and even testing by the factory and US. It's not to say non significant part substitutions can't be made if needed, but design changes and cloning is a whole different ball or wax.