One set equals five. This dumbbell allows one hand operation and one-second adjustment by rotating to your desired position conveniently----Clockwise to decrease weights while counterclockwise to increase weights. It provides you with multiple exercise and training methods. You can build muscle strength, increase bone density, release metal stress and enhance cardiopulmonary function. Just enjoy full body workout and strength training with the practical adjustable dumbbell set! 5-Level Adjustable Weight: This dumbbell features 5-level adjustments of 2.5kg, 5kg, 7.5kg, 10kg and 12.5kg. You can easily change the weight by turning the weight dial in one second. It can meet your different training requirements and let you choose the most suitable and comfortable position shown by a clear weight indicator. Non-slip Handle and Safety Lock: The single dumbbell features an ergonomic handle with anti-slip textured surface, offering you a comfortable and firm grip during exercising. In addition, with the safety lock system, the weight plates can be fixed to the handle firmly and tightly without worrying about falling off. Compact Size and Easy Storage: Having this 1-set of dumbbells equals getting 5-sets of dumbbells, which can save 80% space for you. This dumbbell can be placed anywhere in your home with the little area occupied. Besides, the tray can hold it stably when not in use and prevent breaking your floors. High-Quality Material: The premium steel weight plate is covered with high-strength nylon coating to ensure great rust resistance for long-lasting use. The adjustable dumbbell tray is made of selected PP material, which has strong toughness and is not easy to break or deform. Full Workout and Wide Application: This dumbbell is suitable for fitting indoor exercise use at home or in the gym. By being used in different ways, it can help build up your biceps muscle, chest muscle, abdominal muscle and back muscle to let you enjoy high-quality fitness, gain multiple benefits and get stronger.