The stem (in 10 centimetre length) weighs a good 200 grams and has a rubber bearing between the clamping bush and stem eyelet. The rubber coating is only one millimetre thick, which is why you shouldn't expect miracles when riding over rough obstacles, but the damping of vibrations can certainly improve comfort on long rides.
PLUS Reduces micro-impacts over long distances
MINUS High weight
Reference/Info tranzxpst
Price 99 Euro
Weight 202 grams (length 100 mm)