A multi-ribbed belt, also called a serpentine belt or poly-V belt, is a flat belt with multiple longitudinal V-shaped ribs. These ribs increase the surface contact with pulleys, allowing for more efficient power transmission and reduced slippage.

Unlike traditional V-belts, a single multi-ribbed belt can drive several engine components at once, such as the alternator, water pump, air conditioning compressor, and power steering pump. This makes it a compact and cost-effective solution in modern engine designs.

The belt is made from durable rubber materials reinforced with synthetic fibers to resist wear and heat. Its flexibility allows it to bend easily around multiple pulleys in tight engine spaces.

Multi-ribbed belts are quieter and require less maintenance compared to older belt systems. They also improve fuel efficiency by reducing mechanical losses.