The CURT Rota-Flex 5th Wheel Trailer Pin Box is designed to endure the ruggedness of the roads you encounter on your journeys, day after day and mile after mile. The Rota-Flex features a pivoting head that moves and controls back and forth movement of the king pin within the hitch which significantly reduces chucking. It also contains a robust rubber compound in its head that absorbs road shock, resulting in less strain and reduced wear and tear on your trailer as you travel. The Rota-Flex is designed to replace Lippert 1621 or 1621HD pin boxes and has an 18, 000-lb. gross trailer weight (GTW). It comes ready to install and uses the same bolts as the original pin box, so it doesn't require any additional hardware for installation. Constructed with high-strength steel and finished with a black powder coating, the Rota-Flex is the ultimate 5th wheel pin box to tackle your towing needs for the road ahead.• Replaces Lippert 1621 or 1621HD 5th wheel pin boxes• Reduces chucking and absorbs road shock• Long jaw with pivoting head• Bolt-on installation with no assembly required• Constructed with steel and a black powder coat finish that protects against rust• Powder-coated lower jaw• 18, 000-lb. towing capacity Rubber compound in head absorbs road shock for reduced wear & tear Designed to replace Lippert 1621 or 1621HD pin boxes 18, 000-lb. gross trailer weight (GTW) | Curt L05 Rota-Flex Pin Box, 18,000 lbs in Black