The Bontrager DuoTrap S speed/cadence sensor is an ANT+ and Bluetooth 4.0 compatible wireless sensor that fits directly into the chainstay of certain Trek bikes. This makes it the perfect solution for measuring your speed and cadence when you have a compatible Trek bike model. With the sensor partially hidden in the frame, you get a clean look that doesn't compromise aerodynamics. So say goodbye to cable ties and unsightly sensors on your front fork or swingarm! The DuoTrap S installs in seconds and provides both speed and cadence signals. Want the perfect sensor set for your Trek bike? Go for the Bontrager DuoTrap S!