The LBS installed magnet on my FX never worked. I took it off and put three of these Amazon Magnets on the pedal spindle as someone here did. I have to tell you it looks better then the big rubber band around the crank, you don't even see the magnets. I had the magnets on hand because I had to purchase them for my road bike. That bike's Wahoo Fitness rubber band cadence magnet that is laying on some street after if broke off during a ride.