3t ionic 25 pro aluminium seatpillar the 3t ionic 25 proaluminium seatpillar places the seat clamp assembly 25 mm behind the seatposts centre line features 3ts difflock seat clamp the difflock coupling is a highly accurate method of setting saddle angle needing only lightweight clamping by side mounted bolts and is especially useful for fine adjustment of saddle setback which can be done without impacting saddle angle fabricated in aluminium alloy with a shot peened black anodized finish