This durable plastic card helps you keep track of who strung your racquet, what type of string was used, (both mains and cross), when it was strung, and the tension of the main and cross strings. Conveniently hanging on your racquetsack you can quickly pick the racquet you want to play with taking into consideration the playing conditions and the string set up of each racquet. The card measures 2.5 inches by 3.5 inches. The suface is designed to be written on and easily cleaned when strings and set up are changed.