The splined alloy Diff Lock coupling is a highly-accurate method of setting saddle angle needing only lightweight clamping by side-mounted bolts. It is especially useful for fine adjustment of saddle setback, which can be done without impacting saddle angle. Ionic‑25 Team Stealth has a carbon-fiber shaft bonded into an alloy head & is finished in our elegant Stealth livery. Note: Standard Diff Lock seat clamp fits only saddles with 7-mm ∅ round-section rails. Saddles with oval rails require oval-rail clamp caps.