Dumbbells are a type of free weights commonly used in strength training and fitness workouts. They consist of a short bar with weighted plates attached to each end. Dumbbells are versatile and can be used for a wide range of exercises targeting various muscle groups, including the arms, shoulders, chest, back, and legs. They are available in different weights, allowing users to adjust the resistance according to their strength and fitness level. Dumbbell exercises are popular for building muscle strength.