These adjustable dumbbells replace 15 sets of weights. Weights adjust from 5 to 52.5 lbs in 2.5 lb increments up to the first 25 lbs. Easy-to-use selection dials for adjusting weights. They are sold as single. Easily switch from one exercise to next and with the turn of a dial you can change your resistance, enabling you to gradually increase your strength. Versatile workout for your legs, back, chest, abs, shoulders and arms.