Lots of trickery in our spring sliders. The smoothest and most stable slider on the market. We use a linear DU bushing on a hardened shaft, along with a shaft stabilizing internal piston. No need to unscrew the nut to remove the spring. The spring cup opposite the adjusting nut is quickly removed with a clip. A four position locking mechanism assists with fine tuning. The Torrington bearing on the adjuster nut allows for easy adjustment and bind free spring travel. This is our 24� (WM251C-2.5) extended coarse thread body for 2-1/2" OD springs.