This speedometer was extremely easy to install. I like that the "O" ring had to be doubled because it seems more secure that way. It has a backlight that will light up at night so that your able to see it. You attach a peice to the back tire and and the display hooks the handle bars. You need to set your tire size when you first install it so that it reads accurately. I tested this against an area I knew the miles of and it proved to be accurate.