A brake drum is a crucial component of the braking system in vehicles. It is a rotating cylinder attached to the wheel hub and operates by increasing friction force, allowing the vehicle to decelerate or stop when the brake is applied. The drum is made of durable materials like cast iron or aluminum to withstand the high temperatures and wear that occur during braking. Brake drums are typically found in older cars and some modern vehicles, especially in the rear wheels. Regular maintenance and inspection are essential to ensure the safety and efficiency of the braking system.