The ball set features an image of a four leaf clover for good luck! The images are dyed right into the surface of the balls so they won't scratch off like other "printed on" custom balls. Make sure to read the fine print for other custom balls because some are literally printed and inks can potentially rub or scratch off under normal use. The process we use ensures the image will last the lifetime of the ball without scratching or rubbing off under normal playing conditions.