A 4x4 system refers to a drivetrain configuration that provides power to all four wheels of a vehicle simultaneously. This system enhances traction and stability, making it ideal for off-road driving and challenging weather conditions. Vehicles equipped with 4x4 systems are often used in rugged terrains, such as mountains or muddy areas, where standard two-wheel drive may struggle. There are two main types of 4x4 systems: full-time and part-time. Full-time 4x4 systems, like those found in some SUVs, distribute power to all wheels at all times, while part-time systems allow the driver to switch between two-wheel and four-wheel drive as needed. This flexibility helps improve fuel efficiency when 4x4 capability is not required.