The Black Mamaba Rapid Adjust seat post, from Rase, lowers and raises the seat for you with nothing more than the pull of a mini-lever. The seat automatically raises or lowers up to nine inches for you on the fly! The shaft itself is supported by a small diameter coil spring which extends when you lower the post. There are 20 individually drilled stops, which are locked into place by a sprung pin. You can purchase the Rase Black Mamba Rapid Adjust seat post at Rase Bike for $349.