Everything in image ① is included. This is a set of one dumbbell bar and two each of large, medium, and small dumbbell plates. Originally, it's a 40kg dumbbell. The dumbbell bar weighs 3.7kg. The large plates weigh 8.9kg (two). The medium plates weigh 6.5kg (two). The small plates weigh 2.1kg (two). *The above numbers were measured with a scale. The scale only measures to one decimal place, so there may be some error from the actual weight. When all the dumbbell plates are attached and weighed (using the scale), it comes to 21KG. The three types of dumbbell plates are in pairs. It's used, but generally clean. Regarding attachment/detachment: Press the button (square nub) indicated by the arrow in image 10 to release the lock, and then you can turn the dials on both ends of the dumbbell bar. Combine the dumbbell plates as you like and set them. Turn the dial and lock it in place (there's a point where the set plates won't all come off the bar) with a click. The dials rotate one at a time. (There are numbers, but they don't really matter). The button (square nub) can be pressed with a screwdriver or something similar. It takes some getting used to at first, but it's easy once you get the hang of it.