Cold air intakes are performance-oriented aftermarket components designed to replace a vehicle's stock air intake system. By drawing cooler air from outside the engine bay, these systems aim to increase engine power and efficiency. Cold air is denser than warm air, allowing more oxygen into the engine for better combustion. When selecting a cold air intake system, consider factors like the fit for your specific vehicle, the type of filter (oiled or dry), and the desired intake pipe material (aluminum or plastic).