A 58kg weight set can refer to a fixed dumbbell, a barbell with plates, or a collection of weight plates, with the specific components and features varying by brand and model. For a barbell set, it usually includes a bar (e.g., an Olympic bar or triceps bar) with a total of 58kg of weight plates, often made of cement or iron coated in rubber or plastic for floor protection and quieter use. For dumbbells, a 58kg set could be a single fixed 58kg dumbbell or a set that can be adjusted up to a total of 58kg.