How it works: The Soccer Pro is an electronic training aid designed to help you learn where to strike the ball when shooting, passing or dribbling. When the soccer ball makes proper contact with the Soccer Pro sensors, lights and sounds are activated. The sensors react in real-time, so you receive immediate feedback about you ball-handling skills. You'll know if you're hitting the ball correctly because the training aid will tell you! Strap it on: Strap the SoccerPro around your right or left shoe with the elastic strap. Position the SoccerPro sensor on the right or left side of your shoe, or on the laces. Make sure the device is secure. Position it for shooting: Center the device on top of the laces and make sure it lies flat on the laces. Make sure that the ballast rests under the shoe on the non-cleat area of the sole. When contact is made with the ball, the sensors will activate to show correct position. Position it for dribbling and passing: Position the device on either side of your shoe. Make sure the ballast rests opposite the SoccerPro to insure sensors are level. When the SoccerPro makes proper contact with the soccer ball, the audible sensors will let you know you've hit the ball correctly. Product Care: Do not submerge in water Do not use on excessive moist playing surfaces Do not use in the rain Use proper judgement - the SoccerPro contains sensitive computer chips. When properly cared for, it will function without fail under normal use. One unit per package. SIZING: Small = Child size 10-12, Youth size 1-4, Women size 5-6. Medium = Youth size 4-6, Women size 7-8, Men size 6-7. (these are all shoe sizes). If a child has a large or wide foot, it will affect the size.