Copper Cups. Made from 99.9% Copper with no inner linings like tin, nickel, steel, or other metals. In Ayurveda, the ancient Indian system of medicine, drinking water stored in copper vessels is known as "Tamra Jal" (meaning Copper water). The US Environmental Protection Agency (EPA) has officially recognised copper as a natural antimicrobial material. Studies show that copper surfaces kill bacteria, viruses, and fungi, making it useful for water purification. Sushruta Samhita, an ancient Ayurvedic text, mentions copper’s antimicrobial and detoxifying properties. Still today, many Indian households store water in copper pots overnight before drinking.