Dramatically reduce chucking while towing your 5th wheel, while improving its durability. The Rota-Flex is a flexible pin box that allows the 5th wheel head and kingpin plate to remain in a horizontal position while in tow, creating a smoother ride, while reducing stress on the trailer and you while you tow! The unique proprietary rubber compound, of the Rota-Flex„¢ pin pox, in conjunction with the jounce stops, work together to absorb the transfer of fore-to-aft motion between your tow vehicle and 5th wheel trailer to protect your most precious cargo. Easy to install bolt-on application fits into the pin box sleeves of the major pin box models found in the RV market today; no assembly required.