A punching bag is a versatile training tool used to enhance strength, speed, and technique in martial arts and boxing. Typically filled with materials like sand, foam, or water, it comes in various shapes and weights to suit different training needs. Punching bags can be hung from a ceiling or mounted on a stand, making them suitable for home gyms or fitness studios. They help improve striking accuracy, stamina, and overall fitness, making them an essential piece of equipment for fighters and fitness enthusiasts alike.