More than 200 times experiments for the best material. Repeated deliberation with Chinese National Team to confirm the technical characteristics. Seeking for perfect hitting sense. Keeping the continuity of Celluloid balls" characteristic on droppoint, sound, rotation, and trajectory. Widely welcomed and accepted by athletes. 100% inspection. All technical index meet the requirements of ITTF"s standards, and the balls shall be tested under the temperature and humidity defined by ITTF. Approved by ITTF and CTTA. Each package comes with 6 balls per pack. Only available in white.