The best feature of this device is that it's quite inexpensive yet it works fairly well.. if something happens to it, you fork over another $10 or so and buy a new one. It's pretty simple and doesn't try to be too fancy.. your speed, your distance, a clock (yawn).. a useless thermometer that will show a ridiculously high temp whenever the sun shines on it. It has a backlight that's not bright enough for my old eyes so I don't bother with it. I kinda like the calories-burned feature, although I have no idea how accurate it is. The interface is a bit klunky but not too awful once you are used to it (the right button switches modes, hold the left button for 2-3 secs to reset the trip odometer.. if you just quickly press the left button the thing starts blinking; I haven't figured out what good that does - press the button again and it stops). The issues: [1] no data backup capability, so when it loses power it loses everything (including your total odometer mileage). It DOES allow you to set a starting mileage (so when you're changing the battery - a fresh one lasts more than a year - you can record the mileage beforehand and input it as a starting point with the new battery rather than starting over from zero). [2] While the computer unit seems impervious to rain, the *sensor* (the unit mounted on your fork that senses the magnet going by on the wheel) is VERY moisture-sensitive - if the road is wet, the sensor stops sensing the magnet and the unit stops working for a while.. get it wet enough times and the sensor becomes very finicky (I am about to replace the one I've had for about 3 years - it works intermittently, especially on humid days! I am going to try to waterproof the new sensor - I'll update this review with results..) [3] I own three of these - the first one I bought has issues with the buttons (gotta press the button three or four times before it registers once) and it's had battery-disconnect issues (sudden unexplained loss of power and loss of all data) a couple of times. (I put it on my "spare bike" that I rarely ride and moved a more reliable unit onto my main bike).UPDATE: I've had no luck whatsoever waterproofing this thing. The computer itself appears impervious to moisture, but any time I ride in the rain or on wet streets, the whole thing will stop working (at first it shows my speed as zero and accumulates no additional distance on the odometer.. then the screen blanks out because it assumes I've stopped riding). I have confirmed that the problem is not the computer itself (I got home from a rainy ride, popped the computer out of its mounting bracket, and inserted it onto the bracket of my other bike which was nice and dry; when I spun the wheel, I got a speed/mileage reading. Popped the unit back onto the wet bike and spun the wheel, and I got zero..) so that means the moisture is affecting the sensor apparatus or the mounting bracket or the wire that connects the two. I've tried sealing the sensor AND mounting bracket with plastic bags, but moisture is still getting in... and I've tried waterproofing them by applying silicone caulk to the holes where the wires enter those units (the only place I can see that could allow moisture to enter), but moisture is still getting in.. I can't imagine that water is seeping in to the wire through its insulation.. nor does it make sense that the magnet mounted on the wheel spoke is somehow less magnetic when it's wet..Meanwhile, be advised that this unit will not work in the rain or even when riding on wet pavement..Four years ago, I purchased one of these and it performed great. I was at 9700 miles on the original battery when I lost it out of my pocket. My bad. The computer part can be taken on and off easily if you don't like to leave it on when you park your bike so it doesn't get stolen or damaged. I was considering buying a different model because the user interface is a little quirky. I accidentally reset it a few times by holding both buttons down and then you wipe out your odometer - you then have to re-enter your wheel diameter, age, weight, miles vs. kilometers, etc. Then you can set the clock and manually set your odometer if you remember where you left off. I then realized that I was used to the quirky interface and I'll try to be more careful not to push both buttons at once when I'm resetting the trip or adjusting the clock for daylight saving. Few other things I noticed - on hot days if you leave it in the direct sun, the LCD will go blank or weak and malfunction - it comes back when it cools down or when you start riding so the breeze can cool it. Also there is a wireless version of this that my son has, and I don't like it as much because you have to remember to turn it on before you start riding or it won't track your miles, and the wired version always starts automatically. Also, if you want longer battery life, shy away from using the backlight, after a few years I could tell the battery was straining with the light and the cyclometer would sometimes dim and reset if I held the light too long.Ok, there is a problem with the reset instructions in the manual. If you hold both the left and right buttons down for more than three seconds it will reset and wipe clean taking you back to the setting to wheel size. I got stumped on the time setting because you need to hold the left button down for two seconds to have it flash 24 hour or 12 hour. Each time through I would hit the right button, which would normally allow you to set the digit and it would go right pass the time setting. It the computer was designed with a back button it would be most helpful. However, if you read the instructions carefully as you are trying to set everything up you will be ok. The other problem is there is a setting for a 26 inch tire for regular bikes, and two for mountain bikes, one of which is for 2.25 inch tire width. I took my bike and the computer to a local bike shop and they were not sure which setting to use. My tire is 1.94 inches and it is hybrid between mountain and regular bicycles. I have went with the 26 inch mountain bike and it seems to be ok. A nice little computer. It turns itself off when not in use and will turn on as soon as you start peddling. I was considering getting a wireless so I would not have to worry about running the wire down to the magnet, but decided to get the wired. The reason of this decision was that I only needed to replace the battery in the computer itself. The wireless requires two batteries. The manual and other instruction on the Internet says to place the magnet 2 mm from the sensor. I thought this was pretty close and might cause a problem. But I did find that I did not have to worry about measuring 2 mm. I attached the sensor to the fork and the magnet to the stoke, spun the tire and it showed it was working. One video from Bell tells about placing the sensor facing out in case something comes between the tire and the stokes, to prevent an accident.It does just what it says and it was very easy to fix on.Excellent trip computer. Bought these for all my friends and family. Very reliable.as describedVery good value for the price. Works well on my son's mountain bike.The zip ties have little bits on them that let you "unzip" them - that's annoying. Hard to get them tight enough with that "feature". They come undone on their own at times. Other than that, it's great! You can always use other zip ties if necessary.Facile à installer ! Très facile a utiliser. Cela s'enlève bien du socle si besoin