Suspension is a good thing, especially on small wheel bikes with high-pressure tires. Our suspension seatpost lets you float above the holes, bumps, and ruts in the road. The BioLogic suspension seatpost uses MCU suspension for ultra smooth and damped suspension action. The stiffness is adjustable for a softer or harder ride. Fits bikes with a inner seatpost diameter of 33.9 mm. 580 mm length. Built for Tern bicycles.