Belt-drive compressors feature a V-shaped belt that connects from a small pulley wheel located on the motor to a larger pulley wheel on the air compressor pump. This causes the pump to spin more slowly than the compressor motor. The speed of the compressor pump rotation is thus always lower than the engine speed, which ensures a quieter operation, longer service life and better compressor characteristics. Belt-drive compressors are often the preferred choice because they offer greater flexibility to adjust the air flow and pressure as needed. They are also less expensive to purchase and are easier to install and maintain.