Compatibility Note: The contents in this package are compatible with 2004-2019 E350 Super Duty, 2003-2019 E450 Super Duty, 2021-2023 E350 & E450 Super Duty; HD Standard valving for commercial and HD use. More Firm. Monotube Design: Monotube body provides fade-free performance and a safe and smooth driving experience. Prevents Foaming: High gas pressure technology keeps the oil from foaming, ensuring reliable performance. Better Control: Gas pressure technology helps maintain consistent damping performance, giving you ultimate control in various driving conditions. Durable Construction: Superior materials ensure that the shocks are resistant to corrosion and wear, offering long-lasting performance.