3t ionic 25 ltd high modulus carbon seatpillar the 3t ionic 25 ltd carbon 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 monocoque design with high modulus carbon fibre