This Thingie was my solution to mount a Cateye Strada Slim Sensor on the base of a 2015 Cannondale 27.5 Trigger Carbon 2 SuperMax Lefty. The Guard Mount was specially designed for the guard that came on the bike. The Guard Mount and Sensor Arm are designed for adjust ability between the sensor and the spoke magnet. The last pic is just some of the prototypes I went thru to work out the contour and shapes. Note: The guard cover on other Cannondale bikes may differ in both contoured shape and the placement of the cable tie down that is used for stability. The only modification to the factory guard was a single 0.150 diameter hole. The Guard Mount has a small recessed hole for piloting the drill once it's mated to the factory guard. I counter sunk the hole on the inside in order for a flat head screw to be flush. Load up the hex nut in the counter sunk hex hole. The sensor is then mounted onto the Sensor Arm with a single zip tie wrap.The Sensor Arm and Guard Mount are then assembled with a single 1/2" flat head screw. The design allows for post sensor mount fine tuning before you screw the guard back onto the bike.