Wolf Tooth Seatpost Clamp – 31.8mm Bolt-On Ultraviolet Purple. The precision-engineered Seatpost Clamp secures your seatpost and looks good doing it.At the heart of the Wolf Tooth Seatpost Clamp is a custom self-aligning bolt and anchor. The M5 bolt includes spherical washer and mates with a cylindrical anchor barrel. This means that threads are always perfectly aligned preventing binding and ensuring consistent clamping force.