What an amazing tool, LOVE IT!

This is perhaps the best purchase I have made for my working out next to only my bike itself! I saw one review here stating that it won't keep track of total miles, but apparently he doesn't know how to use it as it does this without any issue for me. I have the model with the speed, cadence and heart rate monitor. With the speed monitor, it automatically figures out your wheel diameter for determining speed by comparing your distance traveled as determined by the GPS to the total number of rotations of your wheel when both are operational. The cadence monitor is not only accurate, but stores the data so you can determine what your avg cadence was for a ride. The HR monitor works great and is just as comfortable as any other commercial model. Also determines elevation and grade so you can determine your ride difficulties! You can change the display to show you any number of your current ride statistics (speed, max speed, avg speed, cadence, avg cadence, HR, max HR, avg HR, % of Max HR, elevation, grade, ride time, lap time, etc...). Offers lap memories of up to 100 laps! Laps can either by instigated by pressing the lap button, on a specific time interval, or at way points predetermined on your route! Set up workouts or race against your previous times on a given route! So much to do with this guy, I just can't get enough. Can be used on up to three different bikes, I use it on my road bike with the cadence, HR and speed sensors and also on my mountain bike with just the HR monitor. Of course if you want the speed and cadence functions for all three bikes, you will need to get three separate sensors for each bike, but the GPS alone records the speed based on the time you are riding and the distance traveled as determined by the GPS. Furthermore, the HR monitor is of course easily transferable from bike to bike. I personally also carry it with me when I go running and hiking and the software allows you to state what the given activity was. The GPS is powerful enough to maintain signal even in the back woods of mtn biking trails! Easily connects to the USB port of your computer (cable included) and is automatically recognized and uploads your saved data to your tracking software (also included).