No more unsightly mufflers on your truck! These performance internal-stack muffler systems hide the muffler inside your 6" stack! 100% American made with 1 year manufacturer warranty against product defects in workmanship and materials. For use in 6" dual straight pipes and mechanical pump engines only. Carbon steel. Fits model years 1995 and older. 6" O.D. x 72" overall length. Installs into the bottom of the stack, presses in snugly to fit and secures with tabs.