The Crank Brothers "Joplin R" all mountain, on-the-fly adjustable seatpost was specifically selected for the HSB Rhythm RDF mountain bike. The huge advantage this seat post has is for cross-country or enduro/ marathon racing. Think of yourself in a cross-country race, you have just finished the big climb with your seat raised to give you maximum pedalling leverage. You are now facing a formiddable descent with rocks, roots and technical drops. With the simple flick of the "joystick" lever on the handlebar, you can now drop the seat up to 3 inches - getting it down low for you to be able to tackle the steep descent. No longer will you get thrown over the bars because your seat is too high for the descent - it will be down and out of the way - not only saving you time if you normally stop to adjust your seat height, but also give you greater speed in the descent as your bike is now set to tackle a tough descent with confidence and speed. Weight: 540 grams.