Soda glass. Do not use abrasive cleansers or steel wool. By characteristics of this glassware, product may contain tiny air bubbles and black dots. Do not place on an unstable surface as it may fall down. By characteristics of this glassware, product surface may frost or smell under high temperature and high humidity. Please wash the product with neutral detergent when it smell or frost. Product size and shape varies in each item due to manufacturing process.