Lug nuts are fasteners used to secure the wheels of a vehicle to its hub. They are typically made of steel and have a hexagonal shape, allowing them to be tightened or loosened with a wrench. Each wheel usually has several lug nuts, which help ensure that the wheel remains firmly attached while the vehicle is in motion. When changing a tire or performing maintenance, it's important to properly torque the lug nuts to the manufacturer's specifications. Over-tightening or under-tightening can lead to issues such as wheel detachment or uneven wear. Regular checks can help maintain the safety and performance of the vehicle, including its tires and brakes.