Opti-Rate Dually System 4x4This fantastic system is perfect for adventure vans at or near GVWR full time, providing enhanced cornering stability and reduced wind sway. The Opti Rate leaf spring pack offers flexibility for different van weights and restores lost ride height, resulting in a nicely leveled stance. With the Falcon 2. 1 Monotube shocks, you can expect improved handling and stability on any terrain. The system is designed to provide a comfortable and safe ride,