A tumbler made with thin glass. A SHIWA series with a smooth indent. A tumbler with a very thin glass. The glass is less than 1mm thick, feeling soft when holding it or drinking out of it. A mold that is used when blowing the glass is the same as the one used to make a normal tumbler. But when the glass is removed from the mold, by sucking in air, the glass has an indent, creating a special pattern. Depending on how hard the air is sucked, each point has a different expression. [note]:This product is not in the box.Due to the nature of glassware, the weight and size, shape of products may vary slightly. Bubbles may be contained in the glass, but that doesn't mean it is defective.