Dumbbells are inexpensive,‎ versatile and easy-to‎-use weights that let you create a variety of workouts to improve your health.‎ Depending on the amount of weight you use,‎ number of repetitions you do and pace at which you use them,‎ dumbbells can help you improve cardiovascular fitness,‎ burn calories,‎ build muscle or increase muscular endurance for sports. Dumbbells are small weights‎,‎ shaped like a Roman letter I‎,‎ resembling mini,‎ single-piece barbells.‎ You purchase dumbbells in different weights,‎ starting with lightweight versions ‎-‎- less than 3 KG ‎-‎- to use during aerobic workouts or while using a treadmill or exercise bike.‎ Heavier dumbbells let you body build.