Ours were like a plastic concert wristband with a little device on it that was about the size of a watch face. Make sure you have them put it on loosely since you will be wearing it for 5 days and can’t take it off. You also get the black tracker box that is in a very nice waterproof bag, similar to the bags you can buy to put your iPhone in when swimming. We pretty much kept our boxes plugged in the whole time. My husband's box would blink red if it wasn't plugged in which is how we could tell our boxes apart.