Just acceptable quality: steel bracket is thin a little low load capacity. The caster is not too durable as it has only one ball bearing raceway in swivel head so if overload or by foreign force the bearing ball may fall out.
Heavy duty with good quality PU tread on firm cast-iron core. The caster is made to operate continuously, it also has greases nipples on bracket steel & wheel's cast-iron core. This makes easy maintenance.