(2) 15 inch 40 lbs Gas Prop Lift Springs Rod Struts Heavy Duty Tool Box Lid Top RV Pair Red Hound Auto Gas Charged Lift Supports Pair Open Length: 15 inches; compressed: 9.5 inches Stroke Length: 5.5 inches Rod Diameter: 6mm || Force: 40 lbs. Compatible with 10mm Ball Mounts