Step 3: Going in!
put the belt on, and wear a shirt long enough to cover it. plug the belt in to the mp3 player, crank up the volume and put it on repeat. i recomend putting the mp3 player in your pocket. test the range by moving close to a cart until it stops. if they stop, awesome! if they don't, GO OUTSIDE then check for shorts (don't do it in the store!), if there aren't any, your mp3 player isn't loud enough.