Reach new goals and explore new roads with a power meter that delivers on accuracy, durability, and reliability. The DFour DUB was designed specifically for Dura-Ace R9100 chainrings. Train using a Quarq power meter without changing your drivetrain. You are working hard, pushing yourself to new heights in some of the toughest conditions. Ride with confidence knowing that your power meter will not quit when you need it the most. Enjoy up to 200 hours of ride time in any weather condition with its IPX7 waterproof rating and 10k temperature compensation; if harsh climates do not hold you back, then you need a product capable of rising to the occasion. That is exactly what the DFour DUB power meter is made for. Train harder, ride faster and unlock your ultimate potential. The DFour DUB power meter brings simplicity and ease-of-use to your training. With MagicZero automatic calibration, there is no need to worry about calibrating before you ride; just jump on your bike and go. DFour DUB features Bluetooth low energy and ANT+ wireless data transfer, delivering power output information directly to your cycling computer.