period mark. Ipoh mineral water has a large production capacity, so different letters should be used to mark the production period. The letter N after the production date on the Ipoh mineral water tank is the period mark. China Resources Ipoh Beverage (China) Co., Ltd. (hereinafter referred to as "China Resources Ipoh") is a professional beverage enterprise under China Resources (Group) Co., Ltd., headquartered in Shenzhen High-tech Industrial Park (North Zone).