Monroe Sensa-Trac Struts and Cartridge features position sensitive damping and the Safe Tech system that combines exclusive precision tapered grooves in the pressure tube with application engineered valving and Fluon banded piston. This strut insert cartridge contains an all weather fluid, rod displaced valving and a unique groove tube that is tapered to provide the optimum ride. The piston rod is hardened and chrome plated for long life. This strut adjusts itself quickly to the changing road conditions and weight conditions and provides consistent performance. During emergency braking, the piston travels beyond the grooves firming up the ride for added safety and control. This cartridge includes a nitrogen gas charged that maintain tire to road contact by reducing aeration. It also comes along with a self-lubricating fluid seal designed to retain gas without excessive wear or friction and is backed by a limited life time warranty.