Lippert Components 155930 L05 Air Ride Pin Box, 18K (Replaces LCI 1621 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)