Professional Referee Substitution Sign, Two-Way (Case: 88×42x3 cm) Football, basketball, football etc. Indicates player substitution in sports. 3x88×42cm case size It is controlled by button. It has a charging time of 10 hours. It has a waterproof feature. Strong polycarbonate case 9 players can record substitutions. It is made for professional and amateur leagues. Assistance is provided for special designs. PRODUCT PREPARATION TIME IS 1 MONTH. Our products are our own production and are guaranteed against manufacturing defects for 2 years.