A PAIR(2) Tanning Bed Gas Spring Strut Rod Shock Lift Prop Arm Tube 21" extended length x 13 " compressed length x 80 LB Pressure Extended Length: 21" (center to center of ball socket ends) Compressed Length: 13" Force: 80 pounds of pressure (Per Prop) End Fitting: 10mm Ball Socket and 10mm Ball Socket Set of Two