Tiger mjc-a mugs are carefully manufactured in japan with attention to details. The vacuum insulated double wall will keep your drinks hot or cold for hours. A copper sheet between the inner bottle and outer enclosure reflects temperature to boost retention for hot or cold beverages. Our stainless steel products are made of sus304 (18/8), known for its excellent corrosion resistance and long-term use. details: - 12oz. / 0.36 l capacity or 16oz. / 0.48 l capacity - vacuum-insulated stainless double wall - one push open and automatic lock - easily washable - easy to hold shape - cold and heat retention - made in japan