A 4x4 drive system is a type of vehicle drivetrain that provides power to all four wheels simultaneously. This system enhances traction and stability, making it ideal for off-road driving and challenging terrains. It is commonly found in SUVs, pickups, and off-road vehicles. There are two main types of 4x4 systems: full-time and part-time. Full-time 4x4 systems distribute power to all wheels at all times, while part-time systems allow the driver to switch between two-wheel drive and four-wheel drive as needed. This flexibility helps improve fuel efficiency on regular roads.