One set equals five. This dumbbell allows one hand operation & 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 & training methods. You can build muscle strength, increase bone density, release metal stress & enhance cardiopulmonary function. Just enjoy full body workout & 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 & 12.5kg. You can easily change the weight by turning the weight dial in one second. It can meet your different training requirements & let you choose the most suitable & comfortable position shown by a clear weight indicator. Non-slip Handle & Safety Lock: The single dumbbell features an ergonomic handle with anti-slip textured surface, offering you a comfortable & firm grip during exercising. In addition,