Lippert Components 155933L07 Air Ride Pin Box, 21K (Replaces LCI 1716 Pin Box) Air bag acts as a buffer between the tow vehicle and coach to absorb road shock and vibration Improves ride and reduces driver fatigue Can be retrofitted to most pin boxes on the market Replaces all popular LCI pin boxes: 16K (1621), 18K (1621), 21K long jaw (1621), 21K (1716), 18K (0719), 21K (1116)