Novak Đoković, one of the best tennis players in the world, is the face of an advertising campaign for MTS, Serbia's biggest mobile operator. This latest advertisement is for an SMS promotion, which is made possible by two Procescom products, Balance portal and PromoBox. Balance portal is a solution that allows users to check their account balance, while offering them value added services. It can be accessed via USSD or an application for IPhone, Android, Windows mobile and Symbian OS. PromoBox integrates with balance portal and offers a number of promotions, in this case, SMS for 1 euro cent.