Wahoo Fitness

I've had this for about a month now and ridden with it at least 20 times. While I wasn't sure I really needed it when I bought it, it has become almost a necessity now that I have used it. I am a senior rider (78 years), and it is wonderful having the few seconds of extra notification of a car approaching from behind. It gives one sound when a car is approaching, a slightly different sound when a string of cars is approaching, and a different sound if the approaching car turns off at another street before passing you. It also has a graphic display on the Element Bike Computer which changes color from green to orange to red as the car approaches. We have a lot of younger (almost everyone is younger than me now days) riders who are very capable (fast) including a fair number of pros (Boulder, Colorado), and the Trackr also alerts me when someone on our many bike trail is approaching on a bike. While I always double check with a mirror, this is a necessity at my age and probably useful for younger riders. The only issue I've found is riding a bikeway that parallels a highway (such as the one along US 36 from Boulder to Denver). The unit kind of goes crazy (constant beeping) in that situation and I have had to turn it off.