All flasks and mugs are boiled in a beeswax and paraffin solution to impregnate the leather and wood with antimicrobial and water resistant properties. The interiors are coated with a food grade resin so they can handle hot, cold, and alcoholic beverages. Small mugs hold two cups, large mugs hold four, small flasks hold two cups, medium four cups, large six cups (1.4 liters). Mugs have a wood base so heat transfer doesn't burn your hands. Hand wash.