Lots of trickery in our dual bearing spring slider. We use a linear ball shaft bearing instead of bronze bushing along with a shaft stabilizing internal piston for the smoothest and most stable slider on the market. the spring cup opposite the adjusting nut is quickly removed with a clip, so you don't have to unscrew the nut to remove the spring. Also a four position locking mechanism and now a coarse thread body. We put a torrington bearing on the adjuster nut so you can adjust it easily and the spring works freely throughout its travel. the length is 24"