A Pair of Gas Prop Lift Springs Rod Struts Heavy Duty Tool Box Lid Top RV 21.7" extended length x 13.5 " compressed length x 160 LB Pressure Extended Length: 21.7" (center to center of ball socket ends) Compressed Length: 13.5" Force: 160 pounds of pressure (Per Prop) End Fitting: 10mm Ball Socket and 10mm Ball Socket Set of Two