Ionic 25 comfort enhances the standard ionic 25 post with shock absorbing technology a polymer damping ring between the head and the difflock clamp decouples the head from the shaft of the post preventing high frequency vibration from being transmitted to the rider ionic 25 comfort helps reduce rider fatigue on todays generation of ultra stiff aero racebike chassis and bikes intended for endurance riding team version has a carbon fiber shaft bonded into an alloy head and is finished in ud gl