I bought these for my 9 year old who really loves to play soccer. He participates in a very competitive league and is always wanting to know where he can improve. I thought these would be a great way for home to put a number to his efforts. Boy was I wrong. The information that these sensor provide is fantastic… if you can ever get the information. Sometimes they load sometimes “oops something went wrong, Try again later” or incorrect mounting when I know they matched Right sensor to Right and Left sensor to left with blue light flashing on the outside. then when you go back, the data is not correct or incomplete or not there at all. There is now way to refresh app or even reboot it all together. Tonight I have put in FIVE two factor authentication codes that they sent to my email only for it to tell me I have the wrong code and then tell me something went wrong. In the year 6 months I have had them, these issues have popped up about 10-15 times. I tried to chalk it up to internet issues, cellular issues, iPhone issues, butt NO!!! It doesn’t matter. Glitchy. Buyer beware.